高频考点例析答案
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2024年中考数学高频考点专题复习——反比例函数的实际应用1.如图,利用已有的一面长为的墙,用篱笆围一个面积为的矩形花圃.设的长为,的长为.(1)求y 关于x 的函数表达式和自变量x 的取值范围.(2)边和的长都是整数,若围成的矩形花圃的三边篱笆的总长不超过,试求出满足条件且用料最省的方案.2.通过实验研究发现:初中生在数学课上听课注意力指标数随上课时间的变化而变化,上课开始时,学生兴趣激增,中间一段时间,学生的兴趣保持平稳状态,随后开始分散,学生注意力指标数y 随时间x (分)变化的函数图象如图所示,当和时,图象是线段;当时,图象是双曲线的一部分,根据函数图象回答下列问题:(1)点A 的注意力指标数是 ;(2)当时,求注意力指标数y 随时间x (分)的函数解析式;(3)张老师在一节课上讲解一道数学综合题需要21分钟,他能否经过适当的安排,使学生在听这道综合题的讲解时,注意力指标数都不低于36?请说明理由.5m 220m ABCD AB ()m x BC ()m y AB BC ABCD 20m 010x ≤<1020x ≤<2040x ≤≤010x ≤<3.如图,帆船A 和帆船B 在太湖湖面上训练,O 为湖面上的一个定点,教练船静候于O 点,训练时要求A 、B 两船始终关于O 点对称.以O 为原点,建立如图所示的坐标系,x 轴、y 轴的正方向分别表示正东、正北方向.设A 、B 两船可近似看成在双曲线y =上运动,湖面风平浪静,双帆远影优美,训练中当教练船与A 、B 两船恰好在直线y =x 上时,三船同时发现湖面上有一遇险的C 船,此时教练船测得C 船在东南45°方向上,A 船测得AC 与AB 的夹角为60°,B 船也同时测得C 船的位置(假设C 船位置不再改变,A 、B 、C 三船可分别用A 、B 、C 三点表示).(1)发现C 船时,A 、B 、C 三船所在位置的坐标分别为A( , )、B( , )和C( , );(2)发现C 船,三船立即停止训练,并分别从A 、O 、B 三点出发沿最短路线同时前往救援,设A 、B 两船的速度相等,教练船与A 船的速度之比为3:4,问教练船是否最先赶到?请说明理由.4.某气象研究中心观测到一场沙尘暴从发生到减弱的过程,开始一段时间风速平均每小时增加2千米,4小时后,沙尘暴经过开阔荒漠地,风速变为平均每小时增加4千米,然后风速不变,当沙尘暴遇到绿色植被区时,风速y (千米/小时),时间x (小时)成反比例关系地慢慢减弱,结合风速与时间的图象,回答下列问题:(1)这场沙尘暴的最高风速是多少?最高风速维持了多长时间;(2)求出当x≥20时,风速y (千米/小时)与时间x (小时)之间的函数关系?(3)在这次沙尘暴的形成过程中,当风速不超过10千米/小时称为“安全时刻”,其余时刻是“危险时刻”.问这次风暴的整个过程中,“危险时刻”一共有多长时间?4x5.为了做好新冠疫情防控工作,某学校要求全校各班级每天对各班教室进行消毒.现有一种备选药物,根据测定,教室内每立方米空气中的药含量y (单位:mg )随时间x (单位:h )的变化情况如图所示,根据图中提供的信息,解决下面的问题.(1)如图反映的是那两个变量之间的关系?哪个是自变量?哪个是因变量?(2)什么时刻每立方米空气中药含量最多?此时药含量是多少?(3)在什么时间范围内,每立方米空气中药含量在增加?在什么时间范围内,每立方米空气中药含量在减少?(4)据测定,当空气中每立方米的药物含量降低到mg 以下时,才能保证对人身无害,若该校课间操时间为40分钟,据此判断,学校能否选用这种药物用于教室消毒?请说明理由.6.水产公司有一种海产品共2104千克,为寻求合适的销售价格,进行了8天试销,试销情况如下:第1天第2天第3天第4天第5天第6天第7天第8天售价x(元/千克)400300250240200150125120销售量y(千克)30404850608096100观察表中数据,发现可以用反比例函数刻画这种海产品每天的销售量y(千克)与销售价格x(元/千克)之间的关系.现假定在这批海产品的销售中,每天的销售量y(千克)与销售价格x(元/千克)之间都满足这一关系.(1)写出这个反比例函数的解析式;(2)在试销8天后,公司决定将这种海产品的销售价格定为150元/千克,并且每天都按这个价格销售,那么余下的这些海产品预计再用多少天可以全部售出?(3)在按(2)中定价继续销售15天后,公司发现剩余的这些海产品必须在不超过2天内全部售出,此时需要重新确定一个销售价格,使后面两天都按新的价格销售,那么新确定的价格最高不超过每千克多少元才能完成销售任务?1167.某中学组织学生到商场参加社会实践活动,他们参与了某种品牌运动鞋的销售工作.已知该品牌运动鞋每双的进价为120元,为寻求合适的销售价格进行了4天的试销,试销情况如表所示: 第1天第2天第3天第4天售价x(元/双)150200250300销售量y(双)40302420(1)观察表中数据,x,y满足什么函数关系?写出用x表示y的函数表达式;(2)若商场计划每天的销售利润为3000元,则每双运动鞋的售价应定为多少元?8.心理学家研究发现,在一节45分钟的课中,学生的注意力随教师讲课的时间的变化而变化,开始学生的注意力逐渐增强,中间学生的注意力保持稳定的状态,随后开始分散,经实验学生的注意力指数y 随时间x(分钟)的变化规律如图所示.(1)一位教师为了达到最好的上课效果,准备课前复习,要求学生的注意力指数至少达到30时,开始上新课,问他应该复习多长时间?(2)如果(1)的这位教师本节新课内容需要22分钟,为了使学生的听课效果最好,问这位教师能否在学生听课效果最好时,讲完新课内容?9.某蔬菜生产基地的气温较低时,用装有恒温系统的大棚栽培一种新品种蔬菜.如图是试验阶段的某天恒温系统从开启到关闭后,大棚内的温度 与时间 之间的函数关系,其中线段 ,表示恒温系统开启阶段,双曲线的一部分 表示恒温系统关闭阶段.请根据图中信息解答下列问题:(1)求 与 ( )的函数表达式;(2)若大棚内的温度低于 时,蔬菜会受到伤害.问这天内,恒温系统最多可以关闭多长时间,才能使蔬菜避免受到伤害?10.某小组进行漂洗实验,每次漂洗的衣服量和添加洗衣粉量固定不变实验发现,当每次漂洗用水量v(升)一定时,衣服中残留的洗衣粉量y (克)与漂洗次数x (次)满足y=(k 为常数),已知当使用5升水,漂洗1次后,衣服中残留洗衣粉2克.(1)求k 的值.(2)如果每次用水5升,要求漂洗后残留的洗衣粉量小于0.8克,求至少漂洗多少次?(3)现将20升水等分成x 次(x>1)漂洗,要使残留的洗衣粉量降到0.5克,求每次漂洗用水多少升?()C y ︒()h x AB BC CD y x 1024x ≤≤10C ︒ 2.5kv x+11.汛期到来,山洪暴发,下表记录了某水库 内水位的变化情况,其中 表示时间(单位:), 表示水位高度(单位: ),当 ( )时,达到警戒水位,开始开闸放水. 02468101214161820141516171814.41210.3987.2(1)在给出的平面直角坐标系中,根据表格中的数据画出水位变化图象,并写出水位高出16米的时间 的取值范围 ▲ .(精确到0.1)(2)请分别求出开闸放水前和放水后最符合表中数据的函数解析式.(3)据估计,开闸放水后,水位的这种变化规律还会持续一段时间,预测何时水位达到 .12.如图,直线与双曲线交于A ,两点,点A 的坐标为,点是双曲线第一象限分支上的一点,连结并延长交轴于点,且.(1)求的值,并直接写出点的坐标;(2)点是轴上的动点,连结,,求的最小值和点坐标;(3)是坐标轴上的点,是平面内一点,是否存在点,,使得四边形是矩形?若存20h x h y m 8x =h /h x /my x 6m 32y x =(0)ky k x=≠B (3)m -,C BC xD 2BC CD =k B G y GB GC GB GC +G P Q P Q ABPQ在,请求出所有符合条件的点的坐标;若不存在,请说明理由.13.泡茶需要将电热水壶中的水先烧到100℃,然后停止烧水,等水温降低到适合的温度时再泡茶,烧水时水温y(℃)与时间x(min)成一次函数关系;停止加热过了1分钟后,水壶中水的温度y(℃)与时间x(min)近似于反比例函数关系(如图).已知水壶中水的初始温度是20℃,降温过程中水温不低于20℃.(1)分别求出图中所对应的函数关系式,并且写出自变量x 的取值范围:(2)从水壶中的水烧开(100℃)降到90℃就可以泡茶,问从水烧开到泡茶需要等待多长时间?14.某种商品上市之初采用了大量的广告宣传,其销售量与上市的天数之间成正比,当广告停止后,销售量与上市的天数之间成反比(如图),现已知上市30天时,当日销售量为120万件.(1)写出该商品上市以后销售量y (万件)与时间x (天数)之间的表达式;(2)求上市至第100天(含第100天),日销售量在36万件以下(不含36万件)的天数;(3)广告合同约定,当销售量不低于100万件,并且持续天数不少于12天时,广告设计师就可以拿到“特殊贡献奖”,那么本次广告策划,设计师能否拿到“特殊贡献奖”?P答案解析部分1.【答案】(1)解:由题意得:,,已有的一面墙长为,,,y 关于x 的函数表达式为(2)解:边和的长都是整数,且, 的值可以为4、5、10、20,围成的矩形花圃的三边篱笆的总长不超过,,的值可以为4、5,当时,,则,当时,,则,满足条件且用料最省的方案为,.2.【答案】(1)24(2)解:设线段(0≤x <10)∵,,∴{b =2410k +b =48 解之:{k =125b =24∴当0≤x <10时的函数解析式为(3)解:当时,代入和得 和∵,20xy =20y x∴=5m 205x∴≤4x ∴≥∴()204y x x=≥ AB BC ()204y x x=≥x ∴ ABCD 20m 220x y ∴+≤x ∴4x =5y =224513x y +=⨯+=5x =4y =225414x y +=⨯+=∴4m AB =5m BC =AB y kx b =+:(024)A ,(1048)B ,12245y x =+36y =12245y x =+960y x=15x =2803x =806552133-=>∴他能经过适当的安排,使学生在听这道综合题的讲解时,注意力指标数都不低于36.3.【答案】(1)2;2;-2;-2;22 ;(2)解:作AD ⊥x 轴于D,连AC 、BC 和OC,∵A (2,2),∴∠AOD=45°,AO=2,∵C 在O 的东南45°方向上,∴∠AOC=45°+45°=90°,∵AO=BO ,∴AC=BC ,又∵∠BAC=60°,∴△ABC 为正三角形,∴AC=BC=AB=2AO=4,∴ ,由条件设教练船的速度为3m ,A、B 两船的速度都为4m ,则教练船所用时间为,A 、B 两船所用时间均为 = ,= , =,> ;∴教练船没有最先赶到.4.【答案】(1)解:0~4时,风速平均每小时增加2千米,所以4时风速为8千米/时;4~10时,风速变为平均每小时增加4千米,10时达到最高风速,为8+6×4=32千米/时,OC ==10~20时,风速不变,最高风速维持时间为20﹣10=10小时;答:这场沙尘暴的最高风速是32千米/时,最高风速维持了10小时(2)解:设y =, 将(20,32)代入,得32= ,解得k =640.所以当x≥20时,风速y (千米/小时)与时间x (小时)之间的函数关系为y =(3)解:∵4时风速为8千米/时,而4小时后,风速变为平均每小时增加4千米, ∴4.5时风速为10千米/时,将y =10代入y = ,得10=,解得x =64,64﹣4.5=59.5(小时).故沙尘暴的风速从开始形成过程中的10千米/小时到最后减弱过程中的10千米/小时,共经过59.5小时.答:这次风暴的整个过程中,“危险时刻”一共经过59.5小时.5.【答案】(1)解:图象反应的是时间x 和每立方米空气中的药含量y 之间的关系;自变量为时间x ;因变量为每立方米空气中的药含量y ;(2)解:从函数图象可得:当x=h 时,空气中药含量最多,最多为1mg ;(3)解:从图象可得:当0<x<h 时,每立方米空气中药含量在增加;当x≥h 时,每立方米空气中药含量在减少(4)解:不能选用这种药物消毒,理由如下:由图象可得,当x=1时,y=,∴,∴学校不能选用这种药物用于教室消毒.6.【答案】(1)解:设 , ∵当x=400时y=30,∴k=400×30=12000,kxk 20640x640x640x151515116116048405⎛⎫-⨯=> ⎪⎝⎭ky x=∴函数解析式为 .(2)解:2104-(30+40+48+50+60+80+96+100)=1600.即8天试销后,余下的海产品还有1 600千克.当x=150时, =80.1600÷80=20(天).答:余下的这些海产品预计再用20天可以全部售出.(3)解:1600-80×15=400(千克),设新确定的价格为每千克x 元. ,解得:x≤60,答:新确定的价格最高不超过60元/千克才能完成销售任务.7.【答案】(1)解:由表中数据得: ∴∴y 是x 的反比例函数,故所求函数关系式为 (2)解:由题意得: 把 代入得: 解得: 经检验, 是原方程的根;∴单价应定为240元8.【答案】(1)解:设DA 的函数关系式为y=kx+b (x≠0),∵y=kx+b 过(0,20),(10,40),∴{b =2010k +b =40,∴{b =20k =2,∴y=2x+20(0≤x≤10);当y=30时,30=2x+20,∴x=5;答:他应该复习5分钟;12000y x=12000150y =120002400x⨯≥6000xy =6000y x=6000y x =()1203000x y -=6000y x =()60001203000x x-=240x =240x =(2)解:设BC 的函数关系式(k 1≠0)(21≤x≤45),∵过B (21,40),∴,∴K 1=840,∴(21≤x≤45),当x=30时,,28﹣5=23,∵23>22,∴这位老师能在学生听课效果最好时讲完新课内容.9.【答案】(1)解:当 时,设 把 代入 得: 所以: (2)解:当 时,经检验: 是原方程的解,且符合题意,所以恒温系统最多可以关闭 小时,才能使蔬菜避免受到伤害.10.【答案】(1)解:∵使用5升水,漂洗1次后,衣服中残留洗衣粉2克,∴v=5,x=1,y=2,∴2=,∴k=-0.1.(2)解:∵v=5,∴y=, ∵反比例函数y=,在x>0的范围内y 随x 的增大而减少,∴当y<0.8时,漂洗的次数x>2.5,∴至少漂洗3次,衣服中残留的洗衣粉量小于0.8克.(3)解:由(1)得y=, 1k y x =14021k =840y x=8402830y ==1024x ≤≤k y x=()1020,k y x =,1020200k =⨯=,200.y x=10y =20010x =,20x ∴=,20x =201010∴-=,105 2.51k +0.15 2.52x x-⨯+=2x 0.1 2.5v x-+∴xy=-0.1v+2.5,即x 2y=-0.1vx+2.5x ,∵将20升水等分成x 次,∴vx=20,∴x 2y=-2+2.5x ,∵y=0.5,∴0.5x 2=-2+2.5x ,即x 2-5x+4=0,∴x 1=4,x 2=1(舍去,x >1),∴当x=4时,每次漂洗用水v=20÷4=5升.答:每次漂洗用水5升.11.【答案】(1)解:在平面直角坐标系中,根据表格中的数据水位变化图象如图所示,;4≤x <8.8(2)解:观察图象当0<x <8时,y 与x 可能是一次函数关系:设y=kx+b ,把(0,14),(8,18)代入得 {b =148k +b =18 解得: {k =12b =14 , y 与x 的关系式为: ,经验证(2,15),(4,16),(6,17)都满足 因此放水前y 与x 的关系式为: (0<x <8).观察图象当x >8时,y 与x 就不是一次函数关系:通过观察数据发现:8×18=10×14.4=12×12=16×9=18×8=144.1142y x =+1142y x =+1142y x =+因此放水后y 与x 的关系最符合反比例函数,关系式为:设 ,则 ,y 与x 的关系式为: .( )所以开闸放水前和放水后最符合表中数据的函数解析式为: (0<x <8)和 .( )(3)解:当y=6时, ,解得: , 因此预计24h 水位达到6m.12.【答案】(1)解:将点A 的坐标为代入直线中,得,解得:,,,B 的坐标为(2)解:如图,作轴于点E ,轴于点F ,则,,,,, ,,,,k y x =144k =144=y x8x ≥1142y x =+144=y x 8x ≥1446=x24x =()-3A m ,32y x =332m =﹣-2m =()2-3A ∴-,=-2(3)=6k ∴⨯-()23,BE x ⊥CF x ⊥BE CF BE CF DCF DBE ∴ ∽DC CF DB BE∴=2BC CD = 13DC CF DB BE ∴==()23B ,3BE ∴=1CF ∴=,作点B 关于y 轴的对称点,连接交y 轴于点G ,则即为的最小值,,设的解析式为,,,解得: ,解析式为,当时,,;(3)解:存在.理由如下:当点P 在x 轴上时,如图,设点 的坐标为 ,过点B 作轴于点M ,四边形是矩形,,()61C ∴,B 'B C 'B C 'BG GC +()()2361B C -' ,,,B C ∴=='=BG GC B C '∴+B C 'y kx b =+()()2361B C -' ,,,3216k b k b =-+⎧⎨=+⎩1452k b ⎧=-⎪⎪⎨⎪=⎪⎩∴B C '1542y x =-+0x =52y =502G ⎛⎫∴ ⎪⎝⎭,1P ()0a ,BM x ⊥ 11ABPQ 190OBP ∴∠=︒,,,,,,,,,经检验符合题意,∴点 的坐标为;当点P 在y 轴上时,过点B 作轴于点N ,如图2,设点 的坐标为,四边形是矩形,,,,,,,经检验符合题意,∴点的坐标为,1==90OMB OBP ∴∠∠︒1=BOM POB ∠∠1OBM OPB ∴ ∽1OB OM OP OB ∴=()23B ,OB ∴==2OM ==132a ∴=1P 1302⎛⎫ ⎪⎝⎭,BN y ⊥2P ()0b , 22ABP Q 290OBP ∴∠=︒2==90ONB P BO ∠∠︒ 2BON P OB ∠=∠2BON P OB ∴ ∽2OB ON OP OB∴==133b ∴=2P 1303⎛⎫⎪⎝⎭,综上所述,点P 的坐标为或.13.【答案】(1)解:停止加热 分钟后,设 , 由题意得: , 解得: ,, 当 时,解得: ,当 时, ,点坐标为 , 点坐标为 , 当加热烧水时,设 ,由题意将 点坐标 代入上式得 , 解得: ,当加热烧水时,函数关系式为 ;当停止加热时 与 的函数关系式为 ; ;(2)解:把 代入 ,得 , 因此从水壶中的水烧开 降到 可以泡茶需要等待 分钟.14.【答案】(1)解:根据题意可知:当时,设y 与x 的函数解析式为,∴,解得:,∴;当时,设y 与x 的函数解析式为,∴,解得:1302⎛⎫ ⎪⎝⎭,1303⎛⎫ ⎪⎝⎭,1k y x =5018k =900k =900y x∴=100y =9x =20y =45x =C ∴()9100,B ∴()8100,20y ax =+B ()8100,100820a =+10a =∴()102008y x x =+≤≤y x 100(89)y x =<≤900(945)y x x =<≤90y =900y x=10x =()100℃90℃1082-=030x ≤≤1y k x =112030k =14k =()4030y x x =≤≤30x ≥2k y x =212030k =23600k =∴综上所述,该商品上市以后销售量y (万件)与时间x (天数)之间的表达式为:;.(2)解:当时,令,解得:,∴,∴销量不到36万件的天数为8天;当时,令,解得: (不符合题意),∴上市至第100天(含第100天),日销售量在36万件以下(不含36万件)的天数为8天;(3)解:当时,令,解得:∴,∴销量超过100万件的天数为6天,当时,令,解得:∴,销量超过100万件的天数为6天,综上所述,销售量不低于100万件,并且持续天数为12天,广告设计师可以拿到“特殊贡献奖”.()360030y x x=≥()4030y x x =≤≤()360030y x x=≥030x ≤≤436x <9x <09x ≤<30x ≥360036x<100x >030x ≤≤4100x ≥25x ≥2530x ≤≤30x ≥3600100x≥36x ≤3036x ≤≤。
逻辑填空高频考点及例题解析下面是店铺整理的公务员行测考试逻辑填空高频考点及例题解析,希望可以对大家的公务员行测考试有所帮助。
逻辑填空高频考点讲解:一.句子对空的解释做逻辑填空的题目,对于题目所涉及的成语,了解成语的基本含义肯定是我们做题的一个基础,在我们积累过程中有个小技巧,那就是要多留个心眼注意形似易混的成语。
我们可以一起来看个例题:例题1.消极完美主义者总是非常仔细地检查任何事情的细枝末节,有时竟达到( ) 的地步。
他们缺少一种适时放弃的智慧,他们所追求的“完美”,不是美学意义上的“完美”,而是一种非常刻板而教条式的“完美”。
填入划横线部分最恰当的一项是:( )A.抱残守缺B.宁缺勿滥C.冥顽不灵D.吹毛求疵【解析】这道题的正确答案是D。
这道题考查的就是解释关系,由“非常仔细地检查任何事情的细枝末节”和最后一句“刻板而教条式的完美”可知吹毛求疵更合适。
吹毛求疵:形容细致到繁琐,挑剔的地步。
例题2. 近几年,不少银行向影视业提供了较多的贷款支持,但迫切渴望融资渠道的中小影视公司仍难以得到扶持,银行往往只是“________”。
而私募基金投资影视业则是“________”:尽管目前号称以影视产业为主要投资方向的基金已有近20只,声称募集资金达200亿元,但披露的有影响力的投资项目却寥寥可数。
依次填入划横线部分最恰当的一项是:( )A.借花献佛小心翼翼B.雪中送炭纸上谈兵C.点到为止画饼充饥D.锦上添花雷大雨小【解析】这道题的突破口在第二空,冒号之后是对二空所填词语的解释,由“尽管目前号称以影视产业为主要投资方向的基金已有近20只,声称达200亿元,但有影响力的投资项目却寥寥可几”可知,二空所填词语应暗含呼声大,实际效果小之意。
所以雷大雨小最合适。
一空的“锦上添花”加双引号,褒义贬用,契合文意。
所以正确答案为D。
二.词或者短语对空的解释在做逻辑填空中,除了句子可能对空处有一定的解释作用外,词语或者短语对空处进行解释也是很常见的,我们可以一起来看看例子:例题3.我们现在认为,严格意义上的地图应该仅仅是对某一片特定区域的记录,它必须严谨如卫星所拍摄到的照片一样。
带答案高考英语词法之过去分词高频考点例题解析单选题1、With a lot of difficult problems ________, the newly-elected president felt greatly relieved.A.to settleB.settlingC.settledD.being settled2、_____, the text became easier for us to learn.A.Explaining new wordsB.New words explainedC.Being explained new wordsD.Having explained new words3、The headmaster decided to put ________ glass on top of the wall to prevent the boys ________ over it . A.breaking ; climbingB.broken ; climbingC.broken ; to climbD.breaking ; to climb4、There were seven people killed in the accident, four children ________. A.includingB.containingC.includedD.contained5、Have you seen Blackpink________ DDU-DU DDU-DU?That’s such a beautiful scene that I dare not have myeyes________ on it.A.dancing;fixingB.dance;fixingC.dance;fixedD.to dance;fixed6、________ to ________ the nature reserve, the local people prevented the workers from entering their villages. A.Opposed; developingB.Opposing; developingC.Opposing; developD.Opposed; develop7、______ into use in April 2000, the hotline was meant for residents reporting water and heating supply breakdowns. A.PutB.PuttingC.Having putD.Being put8、LinaBell, the Disney’s new pink fox character________recently to Duffy Friends toyline at Shanghai Disneyland, has gone viral among Chinese consumers, with netizens________its meet-and-greets videos in Disney resort. A.was introduced … spreadB.introduce d … spreadingC.having been introduced … spreadingD.introducing … to spread9、Sales of low-calorie food rose by 50% ________ with those in May. A.comparingB.compareC.comparedD.were compared10、Mrs. White showed her students some old maps________ from the library.A.borrowedB.to be borrowedC.to borrowD.borrowing11、---What are you mailing, Ryan?---A textbook________a new method of teaching physics. I want my friends to take a look at it.A.is based onB.based onC.basing onD.which based upon12、________ to helping those in need in the town, Old Tim was respected as a figure of great honor. A.DevotedB.DevotingC.Having devotedD.Devote13、Only by shouting at the top of his voice _________________.A.he was able to make himself hearB.he was able to make himself heardC.was he able to make himself hearD.was he able to make himself heard14、______ in the book, he didn’t hear the sound.A.BuryingB.To be buriedC.Having been buriedD.Buried15、It is one of the most interesting stories___________ in the magazine so far this year.A.foundB.being foundC.to findD.finding16、________ the answer several times , he still couldn’t answer the question.A.Having toldB.Having been toldC.Being toldD.Telling17、In the restaurant I found him ________ in the corner, with his whole attention ________ on the man next to him. A.sitting; fixingB.sat; fixedC.seated; fixingD.seated; fixed18、The fireman told us the troubles they had ________the fire________ .A.getting; controlledB.got; controlledC.got; to controlD.getting; to control19、The watch ____ on his way to school is made in Hongkong.A.lostB.losingC.having lostD.loses20、Jill was sitting on the floor, ________.A.boxes surroundingB.was surrounded by boxesC.is surrounded by boxesD.surrounded by boxes21、_________ in the deserted island for a week, the two students were finally spotted by the passing fishing boat. A.Having lostB.LostC.Being lostD.Losing22、The fish _____ bad,the children left much of ____ it.A.tasted,untouchedB.tasting,untouchedC.tasting,untouchingD.tasted,untouching23、He tried to get his work ________ in the medical circles.A.to recognizeB.recognizingC.being recognizedD.recognized24、The expert _______ to the meeting came from different countries around the world.A.invitingB.are invitingC.being invitedD.invited25、When he looked up, he suddenly found himself_______ by a group of teenagers.A.to be surroundedB.surroundedC.be surroundedD.having been surrounded26、 ________ with the size of the whole earth,the biggest ocean does not seem big at all. A.CompareB.When comparingC.ComparingD.When compared27、This year’s charity ball was the most successful ever, as ______ by the number of tickets ______.A.being witnessed; soldB.was witnessed; having been soldC.witnessed; soldD.being witnessed; having been sold28、When painted and furnished with furniture, ________.A.we found a great new restaurant near the flatB.you will feel more comfortable living in the houseC.the house will be used for a nurseryD.we can sell the apartment for much more money29、Waking up in the morning, Tom was surprised to find himself________ with a large carpet. A.coveringB.coveredC.coverD.to cover30、Prices of daily goods ________ through a computer can be lower than store prices.A.to be boughtB.are boughtC.boughtD.are being bought31、Tom looked at Jenny, with tears his eyes, and shouted out the words in his heart for years.A.filling; hidingB.filled; hiddenC.filling; hiddenD.filled; hiding32、________(base) on a true story, the film attracts many people, whether they are old or young. A.BaseB.BasingC.BasedD.To base33、Misunderstandings________ from lack of communication,unless________ properly,may lead to serious problems.A.arisen; dealt withB.arising; dealt withC.rising; dealing withD.risen; dealing with34、With an examination ________, the students felt relaxed and enjoyed themselves a whole night. A.being takenB.takenC.takeD.taking35、He raised his voice to make himself___________.A.understoodB.understandC.to be understoodD.to understand36、I’m not very good at English, but I can make myself _______. A.understandB.understoodC.to understandD.to be understood37、During the COVID-19 outbreak, many people ________ to stay inside are looking for new hobbies. A.were forcedB.had been forcedC.are forcedD.forced38、When________ what they needed most, the kids said they wanted to be felt important and loved. A.askingB.to be askedC.askedD.to ask39、(2016·北京)______ over a week ago, the books are expected to arrive any time now. A.OrderingB.To orderC.Having orderedD.Ordered40、We remained _____ in the traffic jam until midnight due to a serious accident.A.stickingB.stuckC.to be stuckD.to have stuck41、And when he saw the mists _________ from the river and the mountain tops ________ by the soft clouds, he was reduced to tears.A.had risen, had surroundedB.being risen, were surroundedC.rising, surroundedD.rising, being surrounded42、________the best in a science competition, the three students were awarded scholarships totaling $21,000. A.To be judgedB.JudgedC.Having judgedD.Judging43、When we got back from the cinema, we found the lamp ________ but the door ________.A.being on; shutB.burning; shuttingC.burning; shutD.on; shutting44、She was too nervous to speak with so many eyes ______ on her.A.fixingB.fixedC.being fixedD.to fix45、________ in painting, John didn’t notice evening approaching.A.AbsorbedB.AbsorbingC.To absorbD.Absorb带答案高考英语词法之过去分词_003参考答案1、答案:C解析:考查非谓语动词。
(带答案)人教版高中英语词法之冠词高频考点例题解析单选题1、I can't tell you _______ way to Wilson's because we don't have _______ Wilson.A.the, theB.the, aC.the, /D.a, the2、Tom with his friends often_________ on Sunday afternoon.A.play the guitarB.play guitarC.plays the guitarD.plays guitar3、While he was investigating ways to improve the telescope, Newton made ____ discovery which completely changed ________ man’s understanding of color.A.a; /B.a; theC./; theD.the; a4、We hope to join hands together and look forward to ________ brighter future.A.不填B.theC.anD.a5、Unfortunately, fifteen-year-old Paige suffers from _______________ rare brain disease, which affects as few as 12 people in the world, and could kill her any day _______________ warning.A.a; withoutB.the; withoutC.a; withD.the; with6、Life is like an ocean; only _______ strong-willed can reach the other shore.A.aB.theC./D.that7、It’s______ comfort to know there’s someone to keep ______eye on the kids.A.a; theB.a; anC./;anD./;the8、We were shocked to hear the news that ________ two Chinese engineers were shot to death in Pakistan. Worse still, ________ one died in hospital afterwards.A./; a thirdB.the; the thirdC.the; a thirdD./; the third9、What _________ pity you didn’t go to ______ concert with us! It was so exciting!A.不填; aB.a; theC.a; 不填D.the; the10、We stood at the top of the mountain______east of the city, watching ____burning sun rising.A.不填; aB.the; aC.the; theD.不填; the11、In face of ________ failure, it is the most important to keep up ________ good state of mind.A./ ; aB.a ; /C.the ; /D./ ; the12、Lesson 10 is ____ most difficult lesson, but it isn’t ____ most difficult lesson i n Book One.A.a, aB.a, theC.the, theD.the, a13、What ______ fun it is to have a good chance to get so close to ______ nature!A.不填; theB.a; theC.不填; 不填D.a; 不填14、John said he would pay ______ second visit to China ______ next month.A.the;/B.the;aC.a;theD.a;a15、Mr. Wang was a man of ________ before he turned ________.A.success, a writerB.a success, writerC.success, writerD.a success, a money16、 --I hear that there was a terrible crash in the subway in Shanghai the other day.--Yes, _____ news came as _____ shock to all of us.A.the; theB.a; /C.the; aD./; a17、Wouldn’t it be wonderful world if we lived in harmony with nature?A.a; 不填B.the; 不填C.a; theD.the; the18、As ________ matter of fact, the couple are cleaning their house in _______ preparation for the new baby’s coming.A.a; aB.不填; 不填C.a; 不填D.the; 不填19、charge用作及物动词时,接名词或代词作宾语。
带答案高考英语语法时态之一般过去时高频考点例题解析单选题1、My father told me that he didn’t ________ school this year.A.approve my leavingB.approve me to leaveC.approve of my leavingD.approve of me to leave2、He had invited nearly all his classmates to his 18th birthday party, but only one third of them ________. A.turned onB.turned toC.turned overD.turned up3、The publication of Great Expectations, which ______ both widely reviewed and highly praised, strengthened Dickens’s status as a leading novelist.A.have beenB.wereC.wasD.will be4、It ________ many years before Michelangelo ________ painting the ceiling of the Sistine Chapel. A.was…finishedB.was…had finishedC.had been…had finishedD.is…finished5、The employee you had thought highly dishonest.A.of provingB.of provedC.of to proveD.of being proved6、I remembered meeting him before, but his name _____ me. A.slippedB.escapedC.forgotD.hit7、In G7 Summit held in Canada, divisions between USA and other countries, in some critics’ opinion, were just papered over but by no means ________ .A.they were fully solvedB.they had been fully solvedC.were they fully solvedD.had they been fully solved8、"Have you been to Beijing?"he said to me. He asked me _______ .A.that you had been to Beijing.B.that if I had been to Beijing.C.if I have been to BeijingD.if I had been to Beijing9、The factory used 65% of the raw materials, the rest of which saved for other purposes. A.isB.areC.wasD.were10、That was not the first time he ______ us. I think it’s high time we ______ strong actions against him. A.had betrayed; takeB.had betrayed; tookC.has betrayed; tookD.has betrayed; take11、I jumped with j oy the moment I ______ my driver’s license in the mail. A.receiveB.receivedC.had receivedD.would receive12、The majority of the office equipment, as well as two windows, ________ repaired yesterday. A.wereB.wasC.areD.is13、We ______ TV when the telephone _______.A.watched; was ringingB.were watching; rangC.watch; ringsD.are watching; rang14、An expert, together with some assistants, ______ sent to help with this work last week. A.isB.areC.wasD.were15、We________ in the street yesterday.A.is meetingB.meetC.metD.have met16、Only when we saw the photos about the air crash_____ how terrible it was.A.had we knownB.we had knownC.did we knowD.we knew17、I know something about Charlie, for he ________ in my brother's company for three months last year.A.had workedB.workedC.had been workingD.would work18、Miss Li ________ as a secretary for five years in the company, and now she is general manager. A.servesB.servedC.had servedD.has served19、We ________ 1000 English words since we ________ to this school.A.learn, comeB.have learning, cameC.have been learning, comeD.have learned, came20、The fellow we spoke ________ no comment at first.A.to makeB.to madeC.madeD.to making21、“Please open the window.” he said to me.→He ________ me ________ the window.A.said to; to closeB.asked; to closeC.told; closingD.said to; please close22、She was so fortunate that she ________ the earthquake. A.survivedB.soughtC.crashedD.destroyed23、The country ______ its borders when a wave of refugees ______ in, which put a severe strain on its social welfare system.A.scarcely opened; floodedB.had scarcely opened; had floodedC.scarcely opened; had floodedD.had scarcely opened; flooded24、—Is this the first time you ________ Harbin?—No. But the first time I ________ here, the city wasn’t so beautiful.A.visited; cameB.had visited; have comeC.have visited; have comeD.have visited; came25、As the great day ____, she grew more and more nervous. A.alarmedB.admittedC.approachedD.appealed26、By the time we _______, a waiter had come over to our table with a smile. A.seatedB.sittingC.sat ourselvesD.were seated27、The telephone________ four times in the last hour, and each time it________ for my roommate. A.has rung; wasB.has been ringing; isC.had rung; wasD.rang; has been28、The accident __________his carelessness was serious and he to answer for it. A.arose from, violateB.arose from; undertookC.arising from; undertookD.result from; is undertaken29、— Have you ever seen that movie?— Yes. When I was in Tokyo. I _______ it three times.A.sawB.had beenC.have seenD.would see30、Two students to the opening ceremony last Friday.A.hundreds; were invited B.hundred; were invitedC.hundreds of; invited D.hundred of; invited31、__________out of the office building, suddenly a car stopped in front of me.A.To comeB.Having comeC.ComingD.The moment I came32、A Chinese spacecraft successfully________ on the surface of Mars on May 22, 2021. A.landsB.landedC.would landD.had landed33、Although the players tried their best, they lost the game in the end and ______ the result.A.ended upB.relate toC.take upD.settled for34、Only after we received the news that they had arrived safely ______ a sigh of relief.A.we did breatheB.we breathedC.breathed weD.did we breathe35、—You've done a good job.—Yes. It ________ us a whole month to finish it.A.takesB.has takenC.tookD.was taking36、By the time she ________ home to Belgium three months later, her outlook ________ completely. A.returned…cha ngedB.had returned…changedC.had returned…had changedD.returned…had changed37、Normally, I would never do anything like skydiving, but I ________ to give it a try since the lessons were free. A.decidedB.had decidedC.would decideD.have decided38、---Professor Li is wanted on the phone. Where is he?--- I saw him coming, but in a minute, he _____.A.will disappearB.has disappearedC.disappearsD.disappeared39、Only when I left my parents for Italy ________ how much I loved them.A.I realizedB.I had realizedC.had I realizedD.did I realize40、—Have you learned Spanish before?—Yes. I ________English for six years in my hometown.A.learnedB.have learnedC.is learningD.learn41、He __________ football for many years when he was young.A.was playedB.playedC.has playedD.had played42、The careless driver is____for the traffic accident that____yesterday.A.to blame;happenedB.to blame;was happenedC.to be blamed;was happenedD.to be blamed;happened43、I ______ video games when my parents suddenly ______ back home.A.was playing; cameB.was playing; was comingC.was playing; hadD.had played; came44、The fitness room ________ last year is the biggest one in my city, but I ________ to since I ________ ill. A.being built: haven't been; had beenB.having being built; hadn't been; wasC.built; haven't been; wasD.built; hadn't been; had been45、-Is your father still teaching at Tsinghua University?-No, he retired three months ago. But he ______________ at the school for thirty years.A.has taughtB.has been teachingC.taughtD.teaches带答案高考英语语法时态之一般过去时_002参考答案1、答案:C解析:考查时态和固定搭配。
2024年全国监理工程师职业资格考试《建设工程案例分析》(土建)高频考点试卷案例(一)背景资料:某新建住宅楼工程,建设单位采用公开招标的方式进行招标并委托招标代理机构编制了招标文件。
事件1:在招标过程中,施工单位A与施工单位B组成联合体C进行投标,其中A符合相应资质条件,B不符合条件。
施工单位D因是外地公司,对当地具体情况不了解,故建设单位带领D公司踏勘项目现场。
经过评标,施工单位E顺利中标,招标人随即向E单位发出了中标通知书,并在签订书面合同后5个工作日内向未中标人退还投标保证金。
事件2:建设单位与中标单位签订了施工合同。
由于工程项目结构复杂,不确定因素多,工期紧,项目部进场后,项目经理主持了设计交底;在现场调研和审图的基础上,向设计单位提出多项设计变更申请。
事件3:施工前施工单位复核了该工程的原始基准点基准线和测量控制点并报监理机构,经专业监理工程师审核批准。
事件4:招标文件中设定的评标条件有:(1)具备项目所在省份的类似工程业绩。
(2)资格审查、技术审查合格之后需要进行二次报价。
(3)中标人须承诺在提前30%的工期竣工。
工程评标过程中,确定了3名评标专家,其中一名是招标人的技术负责人。
剩余两名从专家库中抽取。
问题:1.联合体C是否符合招标要求?在招投标过程中,是否存在不妥之处?并说明理由。
2.指出事件2中的不妥之处。
并写出正确做法。
3.事件3中,施工前专业监理工程师对施工单位报送的施工测量成果应检查、复核的内容是什么?4.指出事件4中有何不妥?并写出正确做法。
案例(一)1.(1)联合体C单位不符合招标要求;理由:联合体投标时,按照资质等级较低的单位确定资质等级。
故应按B单位资质,不符合投标要求。
(2)不妥之处一:建设单位带领D公司踏勘项目现场;正确做法:招标人不得组织单个或者部分潜在投标人踏勘项目现场。
不妥之处二:建设单位在签订书面合同后5个工作日内向未中标人退还投标保证金;正确做法:招标人最迟应在签订书面合同后5日内向中标人和未中标人退还投标保证金。
2023年安全工程师-安全生产事故案例分析考试历年高频考点真题摘选附带答案第1卷一.全考点押密题库(共50题)1.(单项选择题)(每题 1.00 分)土方开挖前应制定专项施工方案。
采用多台挖土机同时开挖基坑时,挖土机之间的距离应大于()。
A. 4mB. 6mC. 8mD. 10m正确答案:D,2.(单项选择题)(每题 1.00 分) 有限空间中可能存在大量的有毒物质,人一旦接触后易引起化学性中毒可能导致死亡。
下列不属于有毒物质的是()。
A. 二氧化硫B. 二氧化碳C. 氯气D. 氨气正确答案:B,3.(单项选择题)(每题 1.00 分) 土石方爆破作业常见的起爆方法有()三种。
A. 电力起爆、导爆索起爆、导爆管起爆B. 火雷管起爆、导火索起爆、导爆管起爆C. 电力起爆、导火索起爆、导爆雷管起爆D. 火雷管起爆、导爆索起爆、导爆雷管起爆正确答案:A,4.(单项选择题)(每题 1.00 分) 破碎机操作前必须对设备机械部分、电气部分及作业环境进行仔细检查,穿戴好完整的劳动防护用品,下列关于破碎机的技术要求说法中,错误的…是()。
A. 作业前必须戴工作帽、发辫应罩在帽内,扣紧袖口,袖口没有扣子时应使用绳、线绑扎B. 破碎机发生故障时,必须停机处理故障。
故障排除后,要由处理故障人员通知,别人才能开动破碎机C. 在破碎机运行中,严禁用手、木棍、竹片、铁伊及其他物件铲、刮、清理或用扫帚清扫D. 不准跨越运转中的破碎机,禁止任何人在破碎机上走或休息,禁止在破碎机上任意放机具、材料、物件正确答案:A,5.(单项选择题)(每题 2.00 分) 拆除高度在()及以上的临时建筑时,作业人员应在专门搭设的脚手架上或稳固的结构部位上操作,严禁作业人员站在被拆墙体、构件上作业。
A. 一层楼B. 2mC. 3mD. 5m正确答案:B,6.(单项选择题)(每题 1.00 分) 安装平面垂直于水平面,主要用来防止人或物坠落的安全网称为()。
选修1 生物技术实践 高频考点例析参考答案
考点一 果酒、果醋的发酵过程
(1)完成图1中的实验流程。
醋酸发酵
(2)洗去浮尘 反复冲洗 (3)酒精发酵 醋酸发酵 泵入空气(氧) (4)酵母菌 CO2 (含氧量少
的)空气、CO 2
(6)不能。
因为酒精发酵时的缺氧环境能抑制
醋酸菌生长,且醋酸菌发酵条件是氧气充足。
(7) 18 ℃~25 ℃ 30 ℃~35 ℃ 【思考】如何设置对照试验来验
证果汁发酵后产生了酒精?
根据对照实验的原则,在单一变量的前提下,用重铬酸钾检测发酵液中生成酒精的方法: 对照组试管中加入2 mL 白酒,实验组分别加入2 mL 发酵前和发酵后的果汁,再分别向三支试管中加入物质的量浓度为3 mol/L 的H 2SO 4溶液3滴,振荡混匀,最后滴加常温下饱和的
重铬酸钾溶液3滴,振荡试管,观察。
考点二 制作泡菜并检测亚硝酸盐含量
(1) 消毒 (2)
乳酸菌是厌氧型微生物,密封后造成缺氧环境;菜坛有裂缝,将导致乳酸菌不能正常生长,而一些杂菌大量繁殖,泡菜会变质。
(3) 提供乳酸菌菌种 (4)
有机物干重减少;种类增加。
(5) 碳源、氮源、生长因子、水、无机盐、适宜的温度、无氧环境。
考点三 微生物的营养代谢与生长
C
考点四 微生物的培养
(1)温度 酸碱度 易培养 生活周期短
(2)灭菌 消毒 损伤DNA 的结构
(3)比例合适
(4)鉴定(或分类)
(5)将未接种的培养基在适宜的温度下放置适宜的时间,观察培养基上是否有菌落产生
(6)灭菌
【思考】如何确认培养基制作与接种操作是否合格?
(1)培养基制作是否合格
如果未接种的培养基在恒温箱中保温1~2 d 后无菌落生长,说明培养基的制备是成功的,否则需要重新制备。
(2)接种操作是否符合无菌要求
如果培养基上生长的菌落的颜色、形状、大小基本一致,并符合接种细菌菌落的特点,则说明接种操作是符合要求的;如果培养基上出现了其他菌落,则说明接种过程中,无菌操作还未达到要求,需要分析原因,重新操作。
考点五 微生物的分离与计数
(1)苯酚 A 稀释平板菌落计数(活菌计数) (2)④的培养基没有加入苯酚作为碳源,⑤培养基中加入苯酚作为碳源 稀释涂布平板法或平板划线 采用固体平板培养细菌时要倒置培养以防止冷凝后形成的水珠滴落在培养基上污染培养基。
(3)5支洁净培养瓶→分别加入相同培养基(加等量的苯酚,用pH 试纸检测这5支瓶内培养基的pH ,用苯酚调试使之相等。
苯酚是唯一的碳源)→分别接种5种等量的来自不同菌株的菌种→在相同的适宜条件下培养(5)C 6H 12O 6――→酶 2C 2H 5OH +2CO 2 C 6H 12O 6+2O 2――→酶 2CH 3COOH +2CO 2+2H 2O ,
C 2H 5OH +O 2――→酶 CH 3COOH +H 2O
相同的时间→再用pH试纸检测这5支瓶内培养基的pH。
苯酚显酸性,不同菌株的菌种降解苯酚的能力不同,5支瓶内培养基中的苯酚被分解的量不同,所以pH不同。
用pH试纸检测这5支瓶内培养基的pH,从而比较不同菌株降解苯酚能力的大小。
(4)培养基灭菌、接种环境灭菌,接种过程无菌操作。
【归纳提升】微生物分离中的无菌技术:获得纯净培养物的关键是防止杂菌污染,无菌技术可从如下四个方面展开:
(1)对实验操作的空间,操作者的衣着和手进行清洁和消毒。
(2)将用于微生物培养的器皿、接种用具和培养基等进行灭菌。
(3)为避免周围环境中微生物的污染,实验操作应在酒精灯火焰附近进行。
(4)实验操作时,应避免已经灭菌处理的材料用具与周围的物品相接触。
考点六植物组织的培养过程及应用
(1)灭菌消毒(2)外植体真菌(霉菌) 细菌(3)果胶
考点七植物激素在组织培养过程中的作用
(1)外植体(2)去分化(脱分化)
(3)①未分化细胞群经分裂形成愈伤组织②当植物激素X与植物激素Y的浓度比大于1时,未分化细胞群分化形成芽③当植物激素X与植物激素Y的浓度比小于1时,未分化细胞群分化形成根
(4)促进细胞的生长(伸长)、分裂和分化细胞分裂素
(5)组织培养形成试管苗的过程属于无性繁殖,后代不发生性状分离
考点八酶的提取
(1)透明圈植酸钠的消耗量(减少量)或磷酸(肌醇)的生成量(产量)
(2)小分子杂质 (3)变性、复性和延伸(长)加热(或高温处理)
(4)果胶酶、纤维素酶、淀粉酶、蛋白酶、脂肪酶(任选答两种即可)。
考点九探究洗衣粉的洗涤效果
(1)加酶和适当提高温度蛋白酶蛋白酶和脂肪酶 (2)专一性
(3)没有差异,因为高温使酶失活。
(4)未运用酶的固定化技术,因为酶未固定在不溶于水的载体上,也不能重复利用。
考点十 DNA分子的提取和分离
(1)植物细胞具有细胞壁,不会吸水涨破,只有通过研磨,才能释放出DNA。
(2)①溶解DNA分子,过滤并除去不溶于NaCl溶液的杂质;②使DNA分子析出,过滤并除去溶于NaCl溶液中的杂质 (3)防止血液凝固 (4) 二苯胺
考点十一血红蛋白的提取和分离
为保持蛋白质的生理活性,防止变性,用缓冲液保持pH的稳定。
考点十二 PCR原理及过程
(1)磷酸基团 3′端
(2)耐高温的Taq-DNA聚合酶选择培养基
(3)变性、复性和延伸 (4)
(5) 遗传疾病的诊断、刑侦破案、古生物学、
基因克隆和DNA序列测定(要求3项以上)。