Effect of NiO addition on the sintering and grain growth behaviour of BaTiO3

化工进展Chemical Industry and Engineering Progress2023 年第 42 卷第 4 期甲烷催化部分氧化制合成气催化剂的研究进展阮鹏1，杨润农1，2，林梓荣1，孙永明2（1 广东佛燃科技有限公司，广东 佛山 528000；2 中国科学院广州能源研究所，广东 广州 510640）摘要：天然气是一种前景广阔的清洁燃料，甲烷作为天然气的主要成分，其高效利用具有重要的现实意义。

在众多甲烷转化途径中，甲烷催化部分氧化（CPOM ）具有能耗低、合成气组分适宜、反应迅速等优势。

本文简要介绍了CPOM 反应机理，即直接氧化机理和燃烧-重整机理；重点综述了过渡金属、贵金属、双金属和钙钛矿这四类CPOM 催化剂的研究现状；分析了反应温度、反应气体碳氧比和反应空速对CPOM 反应特性的影响；阐述了积炭和烧结这两种催化剂失活的主要原因及应对措施。

根据研究结果可知，通过选取合适的催化剂组分、采用优化的制备方法、精确控制催化剂活性组分分布和微观结构等措施，可以保证更多的有效活性位更稳定地暴露在催化剂表面，以此提高催化性能（包括甲烷转化率、合成气选择性、合成气生成率、反应稳定性等）。

最后指出了对CPOM 催化剂微观结构的合理设计与可控制备以及对CPOM 反应机理的深入研究仍将是今后关注的重点。

关键词：甲烷；部分氧化；催化剂；合成气；多相反应中图分类号：TE644 文献标志码：A 文章编号：1000-6613（2023）04-1832-15Advances in catalysts for catalytic partial oxidation of methane to syngasRUAN Peng 1，YANG Runnong 1，2，LIN Zirong 1，SUN Yongming 2(1 Guangdong Foran Technology Company Limited, Foshan 528000, Guangdong, China; 2 Guangzhou Institute of EnergyConversion, Chinese Academy of Science, Guangzhou 510640, Guangdong, China)Abstract: Natural gas is a promising clean fuel. The efficient use of methane, the major component of natural gas, is of great practical importance. Among many methane conversion routes, catalytic partial oxidation of methane (CPOM) has the advantages of low energy consumption, suitable syngas fraction and rapid reaction. This paper briefly introduced the CPOM reaction mechanisms (i.e. direct oxidation mechanism and combustion-reforming mechanism), reviewed the current research on four types of CPOM catalysts (i.e. transition metal, noble metal, bimetal and perovskite catalysts), analysed the effects of reaction temperature, carbon to oxygen molar ratio of reactant gas and reaction space velocity on CPOM reaction characteristics, and explained the two main causes of catalyst deactivation (i.e. carbon deposition and sintering) together with their countermeasures. According to the results of the research, the catalytic performance (including methane conversion, syngas selectivity, syngas yield, reaction stability) could be improved by selecting suitable catalyst components, adopting an optimized preparation method and precisely controlling the distribution of active components and microstructure of the catalyst. These method could ensure that more active sites are consistently exposed to the surface of catalyst. Finally, it综述与专论DOI ：10.16085/j.issn.1000-6613.2022-1109收稿日期：2022-06-13；修改稿日期：2022-08-22。

初二英语新能源技术与应用阅读理解30题1<背景文章>Solar energy is one of the most important forms of renewable energy. It comes from the sun and can be converted into electricity or heat. The principle of solar energy is based on the photovoltaic effect. When sunlight hits the solar panels, the photons in the sunlight excite the electrons in the solar cells, causing them to flow and generate an electric current.Solar energy has many advantages. Firstly, it is clean and environmentally friendly. It does not produce any pollutants or greenhouse gases. Secondly, it is abundant and free. The sun shines every day, so we can always get solar energy. Thirdly, it is reliable and long-lasting. Solar panels can last for more than 25 years with proper maintenance.Solar energy can be used in many applications. For example, it can be used to power homes, businesses, and schools. It can also be used to charge electric vehicles and power remote communication devices. In addition, solar energy can be used in agriculture to pump water and power irrigation systems.1. What is the principle of solar energy?A. Based on the wind power effect.B. Based on the hydro power effect.C. Based on the photovoltaic effect.D. Based on the nuclear power effect.答案：C。

探究新能源的必要性英语作文英文回答：The exploration of new energy sources has become an imperative necessity in the modern era, driven by an array of compelling factors.1. Depletion of Fossil Fuels: Fossil fuels, the primary source of energy for centuries, are finite in nature. As we continue to rely heavily on these non-renewable resources, their depletion is a looming threat that demands urgent action. The finite nature of fossil fuels also means that their prices are subject to volatility, making energy supply vulnerable to external factors.2. Climate Change Mitigation: The burning of fossil fuels releases greenhouse gases into the atmosphere, contributing significantly to climate change. The adverse effects of climate change, such as rising sea levels, extreme weather events, and biodiversity loss, necessitatethe transition to cleaner and more sustainable energy sources.3. Environmental Protection: Fossil fuel extraction and production can have detrimental impacts on the environment, leading to air and water pollution, land degradation, and habitat destruction. New energy sources offer the potential to minimize these environmental concerns, promoting a cleaner and healthier planet.4. Energy Security: The reliance on imported fossilfuels can compromise national energy security, making countries vulnerable to disruptions in supply andgeopolitical instability. Diversifying energy sources through the exploration of new and indigenous resources can enhance energy independence and resilience.5. Technological Advancements: Advancements in renewable energy technologies, such as solar and wind power, have made them increasingly cost-effective and efficient. These breakthroughs provide opportunities to harness clean and sustainable energy sources at a competitive price.6. Economic Growth and Innovation: The development of new energy industries can stimulate economic growth and create new jobs. Research and innovation in renewable energy technologies drive technological advancements, leading to spillover benefits in other industries and sectors.7. Sustainability for Future Generations: The exploration of new energy sources is crucial for ensuring the sustainability and well-being of future generations. By transitioning to renewable and sustainable energy, we can preserve the planet's resources and mitigate the environmental challenges that lie ahead.中文回答：新能源探索的必要性。

新能源不久将会取代石油英语作文英文回答：In my opinion, it is inevitable that new energy will eventually replace oil as the primary source of energy inthe future. There are several reasons for this shift. First of all, the environmental impact of burning fossil fuelslike oil is becoming increasingly apparent, with climate change and air pollution becoming major concerns worldwide. As a result, there is a growing push towards cleaner and more sustainable energy sources.One of the most promising alternatives to oil is renewable energy, such as solar, wind, and hydropower. These sources are abundant, clean, and can be harnessed ina more sustainable way than oil. For example, solar panels can be installed on rooftops to generate electricity, while wind turbines can be set up in windy areas to produce power. These technologies are constantly improving and becoming more cost-effective, making them more attractive optionsfor energy production.Another factor driving the transition to new energy is the finite nature of oil reserves. As oil becomes more scarce and expensive to extract, it makes sense to investin alternative energy sources that are more abundant and readily available. This shift is already happening in many countries, with governments and businesses investing heavily in renewable energy projects.Furthermore, advancements in technology are making new energy sources more efficient and reliable. For example, electric vehicles are becoming increasingly popular as battery technology improves, making them a viable alternative to traditional gas-powered cars. This trend is likely to continue as more research and development is done in the field of clean energy.Overall, while oil will still play a role in the global energy mix for the foreseeable future, it is clear that new energy sources will gradually take its place as the dominant form of energy production. This transition isnecessary for the health of our planet and future generations.中文回答：在我看来，新能源不久将会取代石油成为未来主要能源是不可避免的。

文章编号:1001-2443(2002)01-0042-04电化学溶解镍阳极法制备纳米NiO韩爱杰,　周幸福,　褚道葆(安徽师范大学化学与材料科学学院,安徽芜湖　241000)摘　要:在无水醇中加入少量有机胺导电盐作为电解液,以金属镍片作为阳极,施加一定的电压,电解得到Ni (OEt )2(acac )2、Ni (OBu )2(acac )2的醇溶液,然后直接水解,经溶胶-凝胶(Sol -gel )过程,形成凝胶体,分别在350℃,600℃煅烧1h 后,均得到具有NaCl 结构的立方晶型的纳米NiO ,粒径为10-15nm.通过F T -IR 、Raman 、XRD 、TEM 检测手段,对镍醇盐配合物和纳米NiO 进行了表征.本文同时讨论了不同镍醇盐配合物制备纳米NiO 的优缺点,发现Ni (OEt )2(acac )2制备的纳米NiO 具有更好的晶型结构和分散性.关键词:电合成;镍醇盐配合物;纳米NiO ;溶胶-凝胶法中图分类号:O646 文献标识码:A 纳米材料研究是目前材料科学研究的热点.NiO 作为一种重要的无机功能材料,具有良好的催化性能,热敏性能等,广泛应用在催化剂[1-2]、电池电极[3-4]、光电转化材料[5-7]、电化学电容器[8-9]等重要领域.由于其各种应用都与其性能有着直接的关系,因此研究纳米NiO 的制备方法具有重要的实际意义. 随着纳米材料科学的发展,纳米材料制备技术日益成熟.近年来,纳米NiO 粉体制备方法有了很大发展[10],如配位-沉淀法,超声波分散法,激光化学法,微波分解法,胶溶法等.但这些方法存在起始原料价格昂贵,设备复杂,反应条件要求苛刻等缺点.新近发展起来的溶胶-凝胶法是制备纳米材料的有效方法,金属醇盐是溶胶-凝胶法制备纳米材料的重要原料.因此,研究金属醇盐的新型合成方法具有重要的实际意义. 有机电解合成一般在常温常压下进行,可通过调节电极电位控制电极反应的方向和速度.根据计算,过电位每改变1V ,活化能可降低40kJ.mol -1,这可以使反应速率增加107倍.有机电解合成方法制备的金属醇盐纯度高,工作环境好,后处理容易,对环境污染少,属于“绿色化学”范畴[11-14]. 本文首次采用无隔膜电解槽,在无水醇体系中电化学溶解金属镍阳极,一步制备纳米NiO 前驱体———镍醇盐配合物.电解液直接水解、干燥、煅烧制备纳米NiO 粉体.采用XRD 、TEM 对纳米NiO 粉体进行表征,并讨论了不同前驱体对制备纳米NiO 的影响.1　实验部分1.1　仪器与试剂 试剂均为分析纯,醇和有机胺导电盐使用前均进一步除水.作阳极材料的金属镍片纯度为99.99%,经除油、活化、清洗处理后作为“牺牲”阳极待用.电解电源采用HY L -A 型直流电源(延边电化学仪器厂).电解槽自行设计,装备一个回流冷凝管,单室电解槽体积为80mL.红外分析采用美国B IO -RAD 公司的F TS -40型光谱仪(K Br 压片).采用日本SHIMADZU 公司制造的XD -3A diffractometer 系统检测NiO 微晶的晶型.日立H -600透射电子显微镜观察NiO 粉体的形貌和大小.拉曼光谱测量采用Labram I 型共聚焦显微拉曼系统(Dilor ,France ),激发线波长为632.8nm 的He -Ne 激光器.镍醇盐配合物在惰性气氛下密封在毛细玻璃管中测定其拉曼光谱.1.2　实验方法 电解槽、电极、醇溶液、导电盐均经过除水处理.并向电解槽内通入经干燥后的氩气,对反应体系进行保护.阴极阳极平行放置在80mL 无隔膜电解槽内,电解槽装备一个回流冷凝管,控制温度为30-40℃.阳极 收稿日期:2001-09-07 基金项目:安徽省自然科学基金(00046112,00043157) 作者简介:韩爱杰(1976-),女,辽宁锦州人,硕士研究生.第25卷1期2002年3月 安徽师范大学学报(自然科学版)Journal of Anhui Normal University (Natural Science )Vol.25No.1Mar .2002面积为3×4cm 2,阴极面积为4×4cm 2.将乙醇、正丁醇分别配制成0.022mol/L 的四乙基溴化胺溶液,用金属镍作“牺牲”阳极,电解过程中滴加少量的乙酰丙酮,得到金属镍醇盐配合物. 电解结束,电解液直接用二次蒸馏水进行水解.先升高温度至40-50℃,在此温度下滴加N H 3・H 2O 调节p H =6.5-7.0,然后加入二次蒸馏水水解,在不断搅拌下降至室温.继续搅拌,溶液粘稠度逐渐增大,得到均匀绿色胶状物.将此胶状物用无水乙醇清洗,以1500rpm 的离心速度进行沉降分离.对下层胶状物再反复醇洗、离心分离二次.放置陈化,得到具有弹性的胶体.将其在红外灯下干燥,得到分散的粉体.将此粉体分别在350℃,600℃煅烧1h ,得到纳米NiO 粉体. 重复上述实验,由正丁醇也可以制备纳米NiO 粉体.2　结果与讨论2.1　镍醇盐配合物的红外及拉曼分析 对电解母液为乙醇的电解液进行提纯,利用红外光谱和拉曼光谱对得到的纳米NiO 的前驱体进行分析.IR 谱中(K Br 压片):1262cm -1-1019cm -1处是C -O 键伸缩振动的特征吸收峰;1585cm -1-1527cm -1是配位的乙酰丙酮基的两个特征吸收峰;2975cm -1-2932cm -1-2842cm -1处是CH 3、CH 2的C -H 伸缩振动吸收峰;669cm -1是Ni -O 键的振动吸收峰.与文献[15]对照说明,乙酰丙酮基已经螯合成功,电解得到的前驱体可能为Ni (OEt )2(acac )2.图1是Ni (OEt )2(acac )2的Raman 光谱,在650cm -1-490cm -1-450cm -1有明显的Ni -O 键吸收峰.Raman shift/cm -1 图2　NiO 的XRD 光谱图1　Ni (OEt )2(acac )2的Raman 光谱 Fig.2XRD spectrucm of nanocrystalline NiOFig.1　Raman spectrum of Ni (OEt )2(acac )2 (a ):calcined at 350℃　(b ):calcined at 600℃2.2　不同镍醇盐配合物制备的纳米NiO 的表征与比较 两种镍醇盐配合物制备的粉体分别在350℃、600℃煅烧后,粉体晶型均为NaCl 结构的立方晶型(J CPDS 4-0835),在2θ(晶面)分别为37(111),43(200),63(220),76(311),80(222)处出现了清晰的特征吸收峰.图2(a )、(b )分别为Ni (OEt )2(acac )2水解后分别经350℃、600℃煅烧得到的粉体的XRD 谱图.350℃煅烧后粉体呈NaCl 结构的立方晶型,600℃时粉体晶型没有变化.随着温度的升高,主峰(200面,2θ=43)变化不大,说明粉体的颗粒尺寸未明显增大.图3(a )、(b )分别为Ni (OEt )2(acac )2制备的粉体在350℃,600℃煅烧后的TEM 照片,图中颗粒呈球形且颗粒度分布均匀.图3(c )、(d )分别为Ni (OBu )2(acac )2制备的粉体在350℃,600℃煅烧后的TEM 照片,随着温度的升高,粉体的粒径明显增大.表1总结了不同镍醇盐配合物制备纳米粉体的过程及粉体的性质.结合TEM照片分析:我们发现Ni (OEt )2(acac )2虽然水解速度快,反应不易控制,但其制备的纳米NiO 具有单分散的球形结构,而由Ni (OBu )2(acac )2制备的纳米NiO出现了团聚现象;并且由Ni (OEt )2(acac )2制备纳米NiO 时,温度升高时纳米粒径增大趋势比由Ni(OBu )2(acac )2制备的小,因此Ni (OEt )2(acac )2更适宜作为制备纳米NiO 的前驱体.表1　不同镍醇盐配合物制备纳米NiO 的比较T able 1Comparison of NiO products prepared by different nickel alkoxo complexes Ni (OEt )2(acac )2Ni (OBu )2(acac )2电解电流(相同电压时)较大较小水解速度很快,不易控制较慢,易控制成胶时间较长较短粉体的聚集状态单分散多分散350℃的粒径-10nm -10nm 600℃的粒径-15nm -30nm 3425卷第1期 韩爱杰,周幸福,褚道葆:　电化学溶解镍阳极法制备纳米NiO(a ) (b )(c ) (d )图3　NiO 粉体的TEM 照片(100×103)Fig.3TEM photograph of NiO nano -particles (100×103)3　结论 采用金属镍为“牺牲”阳极,直接电解合成纳米材料前驱体,克服了传统化学方法合成金属醇盐步骤多,产率低及后续分离繁琐等缺点;使用电合成得到的不同前驱体制备的纳米NiO 性能各异,Ni (OEt )2(acac )2水解速度快,反应不易控制,但其制备的纳米粉体呈单分散,煅烧时粒径变化小,粒径为10-15nm.参考文献:[1]　G abr R M ,El -Naimi A N ,Al -Thani M G.Effect of thermal treatment on the kinetics and sintering characteristics of nickel hydroxide as aprecursor for the thermal genesis of nickel oxide catalyst [J].Thermochimica Acta ,1992,197:307-318.[2]　Christrosfova St G ,Danova N ,G eorgieva M ,Argirov O K ,Mehandzhiev D.Investigation of a nickel oxide system for heterogeneous oxidationof organic compounds [J].Applied Catalysis A :G eneral ,1995,128:219-229.[3]　Ken -ichiro Ota ,Shigenori Mitsushima ,Shigemi Kato ,Shuuji Asano ,Hideaki Y oshitake.Solubilities of nickel oxide in molten carbonate [J].JElectrochem Soc ,1992,139(3):667-671.[4]　Varkey A J ,Fort A F.Solution growth technique for deposition of nickel oxide thin films [J].Thin Solid Films ,1993,235:47-50.[5]　Masaya Chigane ,Masaml lshikawa.Characterization of electrochromic nickel oxide thin film prepared by anodic deposition [J].J Chem Soc Fara 2day trans ,1992,88(15):2203-2205.[6]　Xiaofeng Chen ,Xingfang Hu ,Jingwei Feng.Nanostructured nickel oxide films and their electrochromic properities [J].Nanostructured materi 2als ,1995,6:309-312.[7]　Y oshiyuki Sato ,Shigeharu Tamura ,Kensuke Murai.Electrochromic properties of nickel oxide films prepared by the oxidation of nickel -carboncomposite films [J].J Appl Phys ,1996,35(12A ):6275-6279.[8]　Kuo -Chuan Liu ,Marc A.Anderson.Porous nickel oxide/nickel filmsfor electrochemical capacitors [J].J Electrochem Soc ,1996,143(1):124-130.[9]　Venkat Srinivasan ,John W.Weidner.An electrochemical route for making porous nickel oxide electrochemical capacitors [J].J Electrochem Soc,1997,144(8):L210-L213.[10]　朱诚意,刘中华,陈雯,何发泉.超微NiO 粉体的制备及其应用现状[J].功能材料,2999,30(4):345-349.[11]　褚道葆,周幸福,林昌健,谭建光.电化学合成金属醇盐的研究[J].高等学校化学学报,2000,21(1):133-135.44安徽师范大学学报(自然科学版)2002年[12]　褚道葆,周幸福,林昌健,谭建光.电化学方法制备高热稳定性锐钛矿型纳米TiO 2[J].电化学,1999,5(4):443-447.[13]　周幸福,褚道葆,韩爱杰,顾家山,林昌健,田中群,谭建光.电化学溶解钛金属直接水解法制备纳米TiO 2[J].物理化学学报,2001,17(4):367-371.[14]　周幸福,褚道葆,顾家山,林昌健,林华水,田中群.钛醇盐电化学合成的研究[J].化学学报,2000,58(11):1327-1331.[15]　John Errington R ,John Ridland ,William Clegg.β-diketonate derivatives of titanium alkoxides :X -ray crystal structures and solution dynam 2ics of the binuclear complexes Ti (OR )3(dik )2[J].Polyhedron ,1998,17(5-6):659-674.ANODE DISSOL UTION METH OD TO PREPARE NANO -SIZED NiOHAN Ai 2jie ,　ZHOU Xing 2fu ,　CHU Dao 2bao(College of Chemistry and Materials Science ,Anhui Normal Universit y ,Wuhu 241000,China )Abstract :Nickel alkoxo complexes were obtained by the anodic dissolution of metallic nickel in absolute ethanol in the presence of Et 4NBr (electric 2conductive additive ).The solution was directly hydrolysis to prepare nano 2sized NiO by Sol 2gel process.The precursor gel was respectively calcined at T =350℃and 600℃for one hour ,and nano 2sized NiO was prepared.F T 2IR ,Raman ,XRD ,TEM had been used to investigate the structure of the precursors and nano 2sized NiO.K ey w ords :electrochemical synthesis ,nickel alkoxo complexes ,nano -sized NiO ,Sol 2gel 5425卷第1期 韩爱杰,周幸福,褚道葆:　电化学溶解镍阳极法制备纳米NiO。

Science &Technology Vision科技视界0引言智能材料在航空工业中应用的越来越广泛,它在飞机蒙皮裂纹监测和结构损伤修复上有很好的应用前景。

智能材料结构可以用作传感器与驱动元件,通过收集结构的信息(如裂纹、损伤等),处理后形成控制激励,改变结构的状态,从而使结构具有自诊断、自适应、自修复的能力[1]。

锆钛酸铅压电陶瓷材料(PZT)是目前应用的最广泛的一种。

它具有较高的机电耦合系数,温度稳定性好等优点,通过添加其他元素还可以制备出多种用途的压电陶瓷,成型后可直接作为传感器和驱动器应用[2]。

近年来的研究表明,一些三元系压电陶瓷材料以其较高的压电性能成为压电材料的研究热点[3~5]。

PNN-PZT 材料的成分为[Pb(Nb 2/3,Ni 1/3)O 3]0.55-Pb (Zr 0.3,Ti 0.7)O 3]0.45,本文通过PNN-PZT 材料的制备和测试分析了制备工艺方法对压电陶瓷的结构和性能的影响,最终确定出提高性能的最佳工艺参数。

1实验过程1.1PNN-PZT 粉体的合成图1PNN-PZT 粉末的准备准备PNN-PZT 粉末的流程见图1。

原料为PbO(纯度:99.7%),TiO 2(99.8%)和ZrO 2(98.9%),Nb 2O 5(99.3%)和NiO(99.83%),重量配比达到[Pb (Nb 2/3,Ni 1/3)O 3]0.55-Pb(Zr 0.3,Ti 0.7)O 3]0.45组分。

加水球磨2小时。

混合好的浆料在烘箱中烘干,并在密封的电炉中进行预烧结,1050°C 保温2小时。

预烧得到的粉末在研钵中碾碎,并进一步加水球磨2小时,以获得更好的PZT 粉末。

干燥浆料后,压碎的粉末用网眼为53微米的筛子去除其中的硬块。

得到粒度分布均匀的粉末。

1.2样品制备粉料经球磨再添加1%粘合剂PVA(polyvinyl alcohol),压制成Ф15mm×1.2mm 的圆片(成型压力300MPa),缓慢升温至700℃排胶。

鼓励替代能源好处英语作文Title: The Benefits of Encouraging Alternative Energy Sources。

In recent years, the promotion and adoption of alternative energy sources have become increasingly important worldwide. This shift towards renewable energy such as solar, wind, hydro, and geothermal power brings forth numerous benefits to both the environment and society as a whole. In this essay, we will delve into the advantages of encouraging alternative energy sources.Firstly, the utilization of alternative energy sources significantly reduces greenhouse gas emissions, thus mitigating the adverse effects of climate change. Unlike traditional fossil fuels such as coal and oil, which release harmful pollutants into the atmosphere when burned, renewable energy sources produce minimal to zero emissions during operation. By transitioning to cleaner energy options, we can combat global warming and preserve thehealth of our planet for future generations.Moreover, embracing alternative energy sources enhances energy security and independence. Unlike finite fossil fuel reserves that are subject to depletion and geopolitical conflicts, renewable energy derives from sources that are abundant and widely distributed across the globe. By harnessing the power of the sun, wind, water, and Earth's heat, nations can reduce their reliance on imported fossil fuels and strengthen their energy resilience.Furthermore, the expansion of alternative energy industries fosters economic growth and job creation. The renewable energy sector is a burgeoning field that offers ample opportunities for innovation, investment, and employment. As governments and businesses invest in clean energy infrastructure and technologies, they stimulate economic activity and generate jobs in manufacturing, construction, engineering, and research and development. Additionally, decentralized renewable energy systems empower communities to become self-sufficient energy producers, thereby bolstering local economies and reducingdisparities in wealth distribution.In addition to environmental and economic benefits, alternative energy sources contribute to public health improvements. The combustion of fossil fuels not only produces greenhouse gases but also emits harmful pollutants such as particulate matter, sulfur dioxide, and nitrogen oxides, which pose significant health risks to humans. By transitioning to cleaner energy sources, we can reduce air pollution levels and alleviate respiratory diseases, cardiovascular ailments, and other health issues associated with poor air quality. Moreover, the deployment of renewable energy technologies in remote and underserved areas can provide access to clean and reliable electricity, improving health outcomes and quality of life for marginalized populations.Furthermore, the integration of alternative energy sources enhances energy diversity and resilience. Unlike centralized fossil fuel-based power systems that are vulnerable to supply disruptions and grid failures, renewable energy systems are often decentralized andmodular, allowing for greater flexibility and reliability. By diversifying our energy mix and incorporating renewable sources alongside conventional ones, we can strengthen our energy infrastructure and enhance its ability to withstand unforeseen challenges such as natural disasters, cyberattacks, and fuel shortages.In conclusion, encouraging the adoption of alternative energy sources offers a multitude of benefits ranging from environmental sustainability and energy security to economic prosperity and public health. By embracing renewable energy technologies and transitioning away from fossil fuels, we can build a cleaner, more resilient, and more equitable energy future for ourselves and generationsto come. It is imperative that governments, businesses, and individuals alike collaborate and invest in the development and deployment of renewable energy solutions to address the pressing challenges of climate change and energy transition.。

新能源有什么好处英语作文New energy sources are seriously amazing! Imagine a world where we don't have to rely on fossil fuels like coal and oil to power our cars, homes, and factories. It sounds like a dream, doesn't it? But it's actually becoming a reality with the help of renewable energy.For starters, renewable energy is super clean. Unlike fossil fuels that release harmful greenhouse gases into the atmosphere, renewable sources like solar and wind don't produce any pollution. That means we can breathe easier and our planet can stay healthier for longer.Plus, renewable energy is a never-ending supply. The sun shines every day and the wind blows constantly. So, unlike fossil fuels that are limited and will eventually run out, renewable energy is a sustainable option for the future. We don't have to worry about running out of energy or causing more harm to the environment.Another cool thing about renewable energy is that it's creating jobs. As more and more people start using renewable sources of power, there's a growing demand for skilled workers in this field. So, not only are we saving the planet, but we're also helping people find meaningful work and contribute to the economy.Finally, renewable energy is just plain cool. Think about it: driving a car that runs on electricity instead of gas? Using solar panels to power your home? It's like we're living in the future!。

2024年6月四级英语试卷Part I Writing (30 minutes)Directions: For this part, you are allowed 30 minutes to write an essay on the topic "The Importance of Cultural Heritage Protection". You should write at least 120 words but no more than 180 words.Part II Listening Comprehension (25 minutes)Section A.Directions: In this section, you will hear three news reports. At the end of each news report, you will hear two or three questions. Both the news report and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D).News Report 1.Questions 1 and 2 will be based on the following news item.A new study shows that urban green spaces can significantly reduce the risk of certain diseases. The research, which was conducted over a five - year period in several major cities, found that people living near large parks or gardens had a lower incidence of respiratory and heart diseases compared to those in areas with little or no greenery.1. What did the new study mainly find?A) Urban green spaces are getting smaller.B) People prefer to live near large parks.C) Green spaces can reduce disease risks.D) Respiratory diseases are on the rise.2. How long was the research period?A) Three years.B) Four years.C) Five years.D) Six years.News Report 2.Questions 3 and 4 will be based on the following news item.A well - known tech company has announced a major breakthrough in battery technology. The new battery is said to be more efficient, longer - lasting, and safer than current models. This could have a huge impact on the development of electric vehicles and portable electronics.3. What is the achievement of the tech company?A) A new type of electric vehicle.B) A major breakthrough in battery technology.C) A new marketing strategy for electronics.D) An improvement in portable electronics.4. Which fields could be influenced by this achievement?A) Only electric vehicles.B) Only portable electronics.C) Both electric vehicles and portable electronics.D) Neither electric vehicles nor portable electronics.News Report 3.Questions 5 to 7 will be based on the following news item.A group of international scientists has discovered a new species of deep - sea fish. The fish was found at a depth of over 2,000 meters in the Pacific Ocean. It has unique physical characteristics that distinguish it from other known species.5. Where was the new species of fish discovered?A) In the Atlantic Ocean.B) In the Indian Ocean.C) In the Arctic Ocean.D) In the Pacific Ocean.6. At what depth was the fish found?A) Over 1,000 meters.B) Over 2,000 meters.C) Over 3,000 meters.D) Over 4,000 meters.7. What makes the new fish different from others?A) Its color.B) Its size.C) Its unique physical characteristics.D) Its living habits.Section B.Directions: In this section, you will hear two long conversations. At the end of each conversation, you will hear four questions. Both the conversation and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D).Conversation 1.Questions 8 to 11 will be based on the following conversation.M: Hi, Lisa. How was your weekend?W: It was great. I went to a concert with some friends.M: That sounds fun. Who did you see?W: A local rock band. They were really good.M: I like rock music too. Do you often go to concerts?W: Not really. This was my first time in a while.8. What did Lisa do on the weekend?A) She went to a movie.B) She went to a concert.C) She went to a party.D) She stayed at home.9. What kind of band did Lisa see?A) A pop band.B) A jazz band.C) A rock band.D) A classical band.10. Does Lisa often go to concerts?A) Yes, she does.B) No, she doesn't.C) She used to.D) She never goes.11. What does the man like?A) Pop music.B) Jazz music.C) Rock music.D) Classical music.Conversation 2.Questions 12 to 15 will be based on the following conversation. W: John, I'm thinking about taking a Spanish course.M: That's a great idea. Why do you want to learn Spanish?W: Well, I'm planning a trip to Spain next year, and I think it will be useful.M: You're right. Spanish is also very useful in business these days.W: Do you know any good language schools?M: There's one near my office. I heard it has very good teachers.12. What is the woman thinking about?A) Taking a French course.B) Taking a Spanish course.C) Taking a German course.D) Taking an Italian course.13. Why does the woman want to learn Spanish?A) She is interested in Spanish culture.B) She has Spanish friends.C) She is planning a trip to Spain.D) She wants to work in Spain.14. What else is Spanish useful for according to the man?A) Only for travel.B) Only for culture.C) For business.D) For nothing else.15. What does the man know about a language school?A) It has cheap courses.B) It has good teachers.C) It has a convenient location.D) It has a lot of students.Section C.Directions: In this section, you will hear three passages. At the end of each passage, you will hear three or four questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D).Passage 1.Questions 16 to 18 will be based on the following passage.The Internet has changed the way we communicate and access information. However, it also brings some problems, such as information overload and the spread of false information. To deal with these problems, we need to develop good information - literacy skills. This includes being able to evaluate the reliability of sources, distinguish between fact and opinion, and manage the amount of information we consume.16. What has the Internet changed?A) Only the way we communicate.B) Only the way we access information.C) Both the way we communicate and access information.D) Neither the way we communicate nor access information.17. What problems does the Internet bring?A) Only information overload.B) Only the spread of false information.C) Both information overload and the spread of false information.D) Neither information overload nor the spread of false information.18. What skills do we need to develop?A) Technical skills.B) Social skills.C) Information - literacy skills.D) Management skills.Passage 2.Questions 19 to 22 will be based on the following passage.In recent years, more and more people are choosing to live in small towns instead of big cities. There are several reasons for this. First, small towns usually have a lower cost of living. Second, they offer acloser - knit community where people can get to know their neighbors better. Third, the environment in small towns is often cleaner and more peaceful.19. What trend is mentioned in the passage?A) More people are moving to big cities.B) More people are living in small towns.C) People are moving from small towns to big cities.D) People are moving abroad.20. What is one advantage of small towns?A) High - paying jobs.B) A lot of entertainment options.C) A lower cost of living.D) Easy access to big cities.21. What can people do in small towns?A) They can only work.B) They can get to know their neighbors better.C) They can enjoy big - city life.D) They can avoid all problems.22. How is the environment in small towns?A) Dirty and noisy.B) Clean and peaceful.C) Polluted.D) Dangerous.Passage 3.Questions 23 to 25 will be based on the following passage.A new study has found that reading books can have a positive impact on our mental health. People who read regularly are less likely to suffer from depression and anxiety. Reading can also improve our cognitive abilities, such as memory and concentration.23. What has the new study found?A) Reading books is a waste of time.B) Reading books can harm our mental health.C) Reading books can improve our physical health.D) Reading books can have a positive impact on our mental health.24. Who are less likely to suffer from depression and anxiety?A) People who watch a lot of TV.B) People who play video games.C) People who read regularly.D) People who do no hobbies.25. What can reading also improve?A) Our physical strength.B) Our social skills.C) Our cognitive abilities.D) Our appearance.Part III Reading Comprehension (40 minutes)Section A.Directions: In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the word bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2. You may not use any of the words in the word bank more than once.The concept of time is something that humans have been trying to understand for centuries. Time is a fundamental part of our lives, yet itis also one of the most difficult things to define _(26)_. We use time to organize our days, plan our activities, and measure the passage of our lives. But what exactly is time?Some scientists believe that time is a physical property of the universe, like space or matter. Others think that time is a human _(27)_, created by our minds to make sense of the world around us. There are also those who argue that time is an illusion, and that there is no such thing as a past, present, or future.Despite these different views, one thing is certain: time is a precious _(28)_. We all have a limited amount of time in our lives, and we need to make the most of it. This means using our time _(29)_ to achieve our goals, whether they are personal, professional, or academic.One way to make better use of our time is to learn how to manage it effectively. This involves setting _(30)_, prioritizing tasks, and avoiding distractions. Another important aspect of time management is learning to say no to things that are not important or that will take up too much of our time.In addition to managing our time, we can also try to _(31)_ our perception of time. This can be done by engaging in activities that weenjoy, which can make time seem to pass more quickly. On the other hand, when we are bored or waiting for something, time can seem to drag on _(32)_.Finally, it is important to remember that time is not just aboutgetting things done. We also need to take time to relax, enjoy life, and spend time with the people we love. After all, life is not just about work and achievement, but also about _(33)_ and relationships.Word Bank:A) accurately.B) construct.C) efficiently.D) endlessly.E) goals.F) illusion.G) limited.H) manage.I) precious.J) property.K) relaxation.L) resource.M) sense.26. A) accurately.27. M) sense.28. L) resource.29. C) efficiently.30. E) goals.31. B) construct.32. D) endlessly.33. K) relaxation.Section B.Directions: In this section, you are going to read a passage with ten statements attached to it. Each statement contains information given in one of the paragraphs. Identify the paragraph from which the information is derived. You may choose a paragraph more than once. Each paragraph is marked with a letter. Answer the questions by marking the corresponding letter on Answer Sheet 2.The Benefits of Bilingualism.A) Bilingualism, or the ability to speak two languages fluently, has been shown to have numerous benefits. For one thing, it can improve cognitive abilities such as problem - solving, memory, and concentration. Studies have found that bilingual individuals tend to perform better on tasks that require these skills than monolingual individuals.B) Another benefit of bilingualism is that it can enhance cultural understanding. People who are bilingual are often more exposed to different cultures, which can lead to a greater appreciation and understanding of cultural differences. This can be especially important in today'sglobalized world, where cross - cultural communication is becoming increasingly common.C) Bilingualism can also have a positive impact on career opportunities. In many industries, being bilingual is seen as an asset. For example, in international business, bilingual employees can communicate moreeffectively with clients and partners from different countries. In thefield of education, bilingual teachers are in high demand, especially in areas with large immigrant populations.D) In addition to these practical benefits, bilingualism can also havea positive effect on mental health. Research has shown that bilingual individuals are less likely to develop age - related cognitive decline,such as dementia. This may be because using two languages keeps the brain active and stimulated.E) However, learning a second language is not without its challenges. One of the main difficulties is grammar. Different languages have different grammar rules, and it can be difficult to master them all. For example, in some languages, the verb comes at the end of the sentence, while in others, it comes in the middle.F) Another challenge is vocabulary. Building a large vocabulary in a second language can take a long time. There are often many words that have no direct equivalent in one's native language, which can make it difficultto understand and use them correctly.G) Despite these challenges, the benefits of bilingualism far outweigh the difficulties. There are many ways to learn a second language, such as taking classes, using language - learning apps, or immersing oneself in a language - speaking environment.H) One effective way to learn a second language is through immersion. This involves living in a country where the language is spoken or spendinga significant amount of time in such an environment. Immersion can help learners pick up the language more quickly and develop a more natural accent.I) Another way to learn a second language is through language exchange. This involves finding a partner who speaks the language you want to learn and who wants to learn your native language. You can then practice speaking with each other, which can be a fun and effective way to improve yourskills.J) In conclusion, bilingualism is a valuable skill that can bring many benefits. Whether it is for cognitive, cultural, career, or mental health reasons, learning a second language is well worth the effort.34. Bilingual individuals may perform better on tasks requiring problem - solving skills. (A)35. Bilingualism can help people understand cultural differences better.(B)36. In international business, bilingual employees have an advantage.(C)37. Bilingualism can reduce the risk of age - related cognitive decline.(D)38. Grammar is one of the main difficulties in learning a second language. (E)39. Building vocabulary in a second language can be time - consuming.(F)40. Immersion is an effective way to learn a second language. (H)41. Language exchange can be a fun way to improve language skills. (I)42. The benefits of bilingualism are greater than the difficulties. (G)43. Bilingualism has many benefits for various reasons. (J)Section C.Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice and mark the corresponding letter on Answer Sheet 2.Passage 1.The sharing economy has emerged as a significant economic trend in recent years. Platforms like Airbnb and Uber have revolutionized the way people travel and get around. These platforms allow individuals to share their resources, such as spare rooms or cars, with others in exchange for money.One of the main advantages of the sharing economy is that it can make better use of underutilized resources. For example, many people have spare rooms in their homes that are empty most of the time. By listing these rooms on Airbnb, they can earn extra income while also providing accommodation for travelers. Similarly, cars are often parked and unusedfor long periods. Through Uber or other ride - sharing services, car owners can use their vehicles to earn money when they are not using them.Another advantage is that the sharing economy can provide more affordable options for consumers. Airbnb often offers cheaper accommodationthan hotels, especially in popular tourist destinations. Ride - sharing services can also be less expensive than traditional taxis in some cases.However, the sharing economy also faces some challenges. One issue is regulation. Since these platforms are relatively new, there are often no clear regulations governing their operations. This can lead to problems such as safety concerns and unfair.。

托福-练习十八(总分35,考试时间90分钟)Passage 1Read the passages and choose the best answer to each question. Answer all questions about a passage on the basis of what is stated or implied in that passage.EFFECTS OF IONIZING RADIATION1 Everyone on Earth is continually exposed to small, relatively harmless amounts of ionizing radiation, known as background radiation, from natural sources such as soil and rock. However, other types of ionizing radiation--x-rays, ultraviolet radiation from the sun, and alpha, beta, and gamma radiation emitted by radioactive isotopes--have the potential to harm the human body. Ionizing radiation has enough energy to remove one or more electrons from the atoms it hits to form positively charged ions that can react with and damage living tissue. Most damage occurs in tissues with rapidly dividing cells, such as the bone marrow, where blood cells are made, and the digestive tract, whose lining must be constantly renewed.2 Exposure to ionizing radiation can damage cells in two ways. The first is genetic damage, which alters genes and chromosomes. This can show up as a genetic defect in children or in later generations. The second type of damage is somatic, which causes victims direct harm in the form of bums, miscarriages, eye cataracts, some types of leukemia, or cancers of the bone, thyroid, breast, skin, and lung. Small doses of ionizing radiation over a long period of time cause less damage than the same total dosage given all at once. Exposure to a large dose of ionizing radiation over a short time can be fatal within a few minutes to a few months later.1. According to the passage, what is one difference between background radiation and other types of ionizing radiation?A. Background radiation is rare in nature, while other types are not.B. Background radiation is less likely to harm the human body.C. Background radiation cannot form positively charged ions.D. Background radiation causes more damage to the environment.2. What types of tissues are harmed most by ionizing radiation?A. Tissues with cells that divide quicklyB. Tissues on the outside surface of the bodyC. Tissues exposed to background radiationD. Tissues with a large number of chromosomes3. All of the following are examples of somatic damage EXCEPTA. genetic defectsB. eye cataractsC. radiation burnsD. lung cancer4. Which exposure to ionizing radiation causes the most serious damage to humans?A. Continuous exposure to background radiation in the environmentB. Small doses of ionizing radiation over a long period of timeC. A single dose of a moderate amount of ionizing radiationD. Exposure to a large amount of ionizing radiation in a short periodTHE COYOTE1 All North American canids have a doglike appearance characterized by a graceful body, long muzzle, erect ears, slender legs, and bushy tail. Most are social animals that travel and hunt in groups or pairs. After years of persecution by humans, the populations of most North American canids, especially wolves and foxes, have decreased greatly. The coyote, however, has thrived alongside humans, increasing in both numbers and range.2 **mon **es from coyotl, the term used by Mexico's Nahuatl Indians, and its scientific name, canis latrans, means "barking dog." The coyote's vocalizations are varied, but the most distinctive are given at dusk, dawn, or during the night and consist of a series of barks followed by a prolonged howl and ending with short, sharp yaps. This call keeps the band alert to the locations of its members. One voice usually prompts others to join in, resulting in the familiar chorus heard at night throughout the West.3 The best runner among the canids, the coyote is able to leap fourteen feet and cruise normally at 25-30 miles per hour. It is a strong swimmer and does not hesitate to enter water after prey. In feeding, the coyote is an opportunist, eating rabbits, mice, ground squirrels, birds, snakes, insects, many kinds of fruit, and carrion--whatever is available. To catch larger prey, such as deer or antelope, the coyote may team up with one or two others, running in relays to tire prey or waiting in ambush while others chase prey toward it. Often a badger serves as involuntary supplier of smaller prey: while it digs for rodents at one end of their burrow, the coyote waits for any that may emerge from an escape hole at the other end.4 Predators of the coyote once included the grizzly and black bears, the mountain lion, and the wolf, but their declining populations make them no longer a threat. Man is the major enemy, especially since coyote pelts have become increasingly valuable, yet the coyote population continues to grow, despite efforts at trapping, shooting, and poisoning the animals.5. According to the passage, the coyote is unlike other North American canids in what way?A. The coyote&#39;s body is not graceful.B. The coyote is not hunted by humans.C. The coyote population has not decreased.D. The coyote does not know how to swim.6. All of the following statements describe the coyote&#39;s vocalizations EXCEPT:A. **municate the locations of other coyotes.B. The coyote uses its distinctive call to trick and catch prey.C. A group of coyotes will often bark and howl together.D. The coyote&#39;s scientific name reflects its manner of vocalizin7. According to the passage, the coyote is an opportunist because itA. nows how to avoid being capturedB. likes to team up with other coyotesC. has better luck than other predatorsD. takes advantage of circumstances8. Which animal sometimes unknowingly helps the coyote catch food?A. WolfB. RodentC. DeerD. Badger9. According to the passage, the chief predator of the coyote isA. the wolfB. the mountain lionC. the humanD. the grizzly bear10. According to the passage, all of the following statements are true EXCEPT:A. The coyote is a serious threat to human activities.B. The coyote is a skillful and athletic predator.C. The coyote hunts cooperatively with other coyotes.D. The coyote survives despite persecution by humans.Passage 2Read the passages and choose the best answer to each question. Answer all questions about a passage on the basis of what is stated or implied in that passage.RURAL CANADA1 In the 1880s, over three-fourths of Canada's population lived outside urban centers. One view of rural Canada at that time portrays it as a vast wasteland of isolated **munities. However, a more accurate view shows that rural Canadians had access to considerable information. The postal service was efficient and inexpensive and connected rural Canadians with the outside world. Many farm families received at least one newspaper through the mail, usually within a day of publication. The daily newspapers of the period were more substantial than those of today, and many reproduced precise accounts of court trials and public events. Rural Canadians read magazines and books and held discussions about them at club meetings.2 Rural Canadians were also able to get together socially. The local school served other functions besides providing formal education, and school districts were often the only sign of political organization in vast regions of the country. **munity valued its one- room schoolhouse as a meeting place, especially during the winter, when work on the farm was much lighter and people had more time for a variety of social and cultural events. People of all ages got together to sing and play musical instruments, perform skits, and play parlor games.3 Between 1880 and 1920, there was a growing exodus from farms to the city, mainly because smaller farms could not afford to modernize their technology and were no longer able to support the entire family. However, most Canadians continued to hold rural values, and artists and writers romanticized the family farm. In the novel Anne of Green Gables (1908), Lucy Maud Montgomery wrote about a young woman who strove to reconcile the beauty and peace of the rural landscape with the need to leave it in order to fulfill her ambitions. For large numbers of young Canadians, growing up meant leaving the farm to find work in the city.1. According to the passage, rural Canada in the 1880s was not an isolated wasteland becauseA. most farms were close to the cityB. education was inexpensiveC. the rural population was growingD. information was available to farmers2. The author makes the point that the postal serviceA. did not reach rural areas until the 1880sB. served an important function in rural CanadaC. provided jobs for many rural CanadiansD. was expensive to operate in rural areas3. Many social gatherings took place during the winter becauseA. there was less work to do on the farmB. there were fewer court trials or political activitiesc. social gatherings were forbidden at other timesD. many holidays occurred in the winter4. According to the passage, the rural school provided all of the following services EXCEPTA. formal educationB. public health clinicsC. political organizationD. social and cultural events5. What reason is given for large numbers of people leaving the family farm?A. There was not enough work on the farm during the winter.B. People grew tired of the social isolation of rural life.C. Small farms could no longer support the whole family.D. Modern farm technology was not available in many areas.6. Which statement best describes the period from 1880 to 1920?A. Literature portrayed a romanticized view of life on the farm.B. More Canadians lived in urban areas than in rural areas.C. **munities began to acquire characteristics of the city.D. People gave up their rural values when they moved to the city.7. The novel Anne of Green Gables serves to illustrateA. the need for farmers to modernize their technologyB. the view of rural Canada as an isolated wastelandC. the importance of social connections in rural CanadaD. the experience of many young Canadians of the periodICE1 Two conditions are necessary for the formation of ice: the presence of water and temperatures below freezing. Ice in the atmosphere and on the ground can assume various forms, depending on the conditions under which water is converted to its solid state~ Ice that forms in the atmosphere can fall to the ground as snow, sleet, or hail. Snow is an assemblage of ice crystals in the form of flakes; sleet is a collection of frozen raindrops, which are actually ice pellets. Hail consists of rounded or jagged lumps of ice, often in layers like the intemal structure of an onion. Ice also forms directly on the ground or on bodies of water. In North America, ice forms in late autumn, winter, and early spring. On very large bodies of water, it may not form until late winterbecause there must be several months of low temperatures to chill such large amounts of water.2 On puddles and small ponds, ice first freezes in a thin layer with definite crystal structure that becomes less apparent as the ice thickens. On lakes large enough to have waves, such as the Great Lakes, the first ice to form is a thin surface layer of slush, sometimes called grease ice, which eventually grows into small floes of pancake ice. If the lake is small enough or the weather cold enough, the floes may freeze together into a fairly solid sheet of pack ice. Pack ice may cover the entire lake or be restricted to areas near the shore.3 Because water expands when it freezes, ice is less dense than liquid water and therefore floats rather than sinks in water. As ice floats on the surface of a lake, ocean, or river, it acts as an insulator and is thus important in maintaining the balance of the ecosystem. Without the insulating effect of floating ice sheets, surface water would lose heat more rapidly, and large bodies of water such as the Arctic Ocean and Hudson Bay might freeze up completely.8. What condition is necessary for water in the atmosphere to change to its solid state?A. A solid cloud cover that absorbs the sun&#39;s heatB. A weather forecast for snow, sleet, or hailC. A position directly above a large body of waterD. A temperature below water&#39;s freezing point9. In paragraph 1, the author makes the point thatA. ice can take a variety of formsB. sleet and snow differ from iceC. in some years ice never forms at allD. ice rarely forms on the ground in cities10. Ice that forms in the atmosphere in the form of layered lumps is known asA. snowB. pack iceC. hailD. grease ice11. All of the following are forms of ice that form on bodies of water EXCEPTA. sleetB. slushC. pancake iceD. pack ice12. Why does ice form later on very large bodies of water?A. Most large bodies of water are located at low elevations or low latitudes.B. It takes several months of cold temperatures to cool a large body of water.C. Large bodies of water are fed by underground springs of warmer water.D. The waves on large bodies of water prevent the water from freezing quickly.13. When ice starts to form on small bodies of water,A. it takes the shape of small floesB. it freezes more quickly in the centerC. its surface feels greasy to the touchD. its crystal structure can be seen14. Which statement is true about pancake ice?A. It forms on puddles and small ponds.B. It falls from the atmosphere to the ground.C. It may become a sheet of pack ice.D. It is the least dense form of ic15. Which of the following is an effect of the density of ice?A. Ice that forms on large lakes has a greasy consistency.B. Each ice crystal is unique, but all are six-sided structures.C. Pack ice is restricted to areas near the shore of a lake.D. Floating ice sheets prevent bodies of water from losing heat.16. The passage mentions all of the following characteristics of ice EXCEPTA. its appearanceB. where it formsC. the rate at which it meltsD. its effect on the ecosystemTHE ROLE OF GOVERNMENT IN THE ECONOMY1 Because most people do not volunteer to pay taxes or police their own financial affairs, governments cannot influence economic activity simply by asking people to pollute less, to give money to the poor, or to be innovative. To accomplish these things, governments have to pass laws. Since the early twentieth century, governments of countries with advanced industrial or service economies have been playing an increasing role in economics. This can be seen in the growth of government taxation and spending, in the growing share of national income devoted to income-support payments, and by the enormous increase in the control of economic activity.2 The large-scale organization of business, as seen in mass production and distribution, has led to the formation of large-scale organizations--corporations, labor unions, and government structures--that have grown in importance in the past several decades. Their presence and growing dominance have shifted capitalist economies away from traditional market forces and toward government administration of markets.3 In the United States, government provides a framework of laws for the conduct of economic activity that attempt to make it serve the public interest. For instance, the individual states and the federal government have passed laws to shield investors against fraud. These laws specify what information has to be disclosed to prospective investors when shares of stocks or bonds are offered for sale. Another important area of law concerns the labor force, such as regulation of work hours, minimum wages, health and safety conditions, child labor, and the rights of workers to form unions, to strike, to demonstrate peacefully, and to bargain collectively through representatives of their own choosing.4 In other nations, the ways in which governments intervene in their economies have varied; however, governments everywhere deal with essentially the same issues and participate in economic activity. Even governments that are reluctant to **merce directly have undertaken large-scale projects such as hydroelectric and nuclear energy developments, transportation networks, or expansion of health, education, and other public services.17. According to the passage, why do governments intervene in economic activity?A. People do not willingly regulate their own business affairs.B. Governments understand the economy better than anyone else does.C. Businesses pay governments to participate in economic activity.D. The economy would fail without the help of government.18. According to the passage, governments intervene in economic activity mainly byA. asking people not to polluteB. requiring innovationC. passing lawsD. producing goods and services19. According to the passage, how has the growth of large-scale organizations such as corporations and labor unions affected capitalist economies?A. It has forced governments to pass laws protecting traditional markets.B. It has destroyed capitalism and replaced it with government ownership.C. It has led to the increasing role of government in economic activity.D. It has caused **petition between large and small businesses.20. In paragraph 3, the author mentions two areas of law that aim toA. serve borrowing and lending institutionsB. restrict the size of corporations and labor unionsC. regulate domestic and international tradeD. protect the rights of investors and workers21. In paragraph 3, the author mentions laws to shield investors against fraud as an example ofA. laws that organize businessB. laws that serve the public interestC. laws that protect the labor forceD. laws that set the price of stocks22. All of the following are given as issues concerning the labor force EXCEPTA. stock ownershipB. health and safetyC. hours of workD. the right to strike23. In paragraph 4, the author states that all governmentsA. use the same economic strategiesB. confront similar economic issuesC. have laws regulating labor unionsD. dislike intervening in markets24. What point does the author make about governments that do not want to regulate business directly?A. They **pete effectively with government-controlled economies.B. They have capitalist economies based on traditional market forces.C. They have no laws for protecting the environment and public health.D. They participate in the economy through public projects and services.25. According to the passage, all of the following are examples of government participation in economic activity EXCEPTA. taxation and spendingB. small business ownershipC. ncome-support paymentsD. transportation networks。