数学运算符号的英文表达
小数、分数、百分数和运算符号
1. 小数表示法
(1) 小数的读法
小数点左边的数通常按基数词读，若为三位以上的数，也可按编码式读法读出，即将数字单个读出；小数点右边的数通常按编码式读法单个读出。
如：
6.86 six point eight six
14.15 fourteen point one five
345.456 three four five point four five six
或three hundred and forty－five point four five six
(2) 小数中“0”的读法
“0”在小数中通常读作nought（英）或zero（美），也可读作字母o。
如：
0.08 （nought）point nought eight 或（zero）point zero eight
9.07 nine point o seven
2. 百分数表示法
百分数中的百分号％读作percent。
如：
6% 读作 six percent
0.6% 读作（nought） point six percent
500% 读作five hundred percent
3. 倍数表示法
倍数表示方法很多，如：
This room is four times as big as mine. 这个房间是我房间的四倍。
This room is three times larger than that one. 这个房间比那个房间大两倍。
The output of coal has doubled. 煤的产量增加了一倍。
My aunt is as old again as I am. 我姑姑年龄比我大一倍。
Productivity is increased three fold. 生产效率提高了两倍。
The volume of the Sun is about 1,300,000 times that of the Earth.
太阳的体积约为地球的1300000倍。
4. 加减乘除式的读法
6+5＝11 Six plus five is eleven 或Six and five is eleven.
11-6＝5 Eleven minus six is five. 或Six from eleven is five.
4×5＝20 Four multiplied by five is twenty.或Four times five is twenty.
20÷4＝5 Twenty divided by four is five. 或Four into twenty goes five. 15:5＝3 The ratio of fifteen to five is three.
32 Three squared is nine.
23 Two cubed is eight.
24 The fourth power of two is sixteen.
X^(1/2)=Y The square root of X is Y.
X^(1/3)=Y The cubic root of X is Y.
a ＞
b a is more than b.
a ＜
b a is less than b.
a ≈
b a approximately equals to b.
a ≠
b a is not equal to b.
5. 分数表示法
(1) 较小分数的一般读写方法。
如：
1/3 one-third 2/3 two-thirds 3/5 three-fifths
(2) 较复杂分数的简明读写方法。
如
22/9 twenty-two over nine
a/b a over b 或a divided by b 43/97 forty-three over ninety-seven
(3) 整数与分数之间须用and连接。
如：
four and a half nine and two fifths
(4) 分数用作前置定语时，分母要用单数形式。
注意下列写法与读法。
如：
a one-third mile1/3英里 a three-quarter majority3/4的多数
常用标点符号用法
常用缩略语表
．period 句号
，comma 逗号
：colon 冒号
；semicolon 分号
！ exclamation 惊叹号
？question mark 问号
￣ hyphen 连字符
' apostrophe 省略号；所有格符号
— dash 破折号
‘’ single quotation marks 单引号
“” double quotation marks 双引号( )parentheses 圆括号
[] square brackets 方括号
《》 French quotes 法文引号；书名号... ellipsis 省略号
¨ tandem colon 双点号
" ditto 同上
ǁparallel 双线号
／virgule 斜线号
＆ampersand = and
～swung dash 代字号
§ section ;
→arrow 箭号；参见号
＋plus 加号；正号
－minus 减号；负号
± plus or minus 正负号
× is multiplied by 乘号
÷ is divided by 除号
＝is equal to 等于号
≠ is not equal to 不等于号
≡is equivalent to 全等于号
≌is equal to or approximately equal to 等于或约等于号≈ is approximately equal to 约等于号
＜is less than 小于号
＞is more than 大于号
≮is not less than 不小于号
≯is not more than 不大于号
≤is less than or equal to小于或等于号
≥is more than or equal to 大于或等于号
％per cent 百分之…
‰ per mill 千分之…
∞infinity 无限大号
∝varies as 与…成比例
√(square) root 平方根
∵since ;
∴hence 所以
∷equals ,
∠angle 角
⌒semicircle 半圆
⊙circle 圆
○ circumference 圆周
πpi 圆周率
△triangle 三角形
⊥perpendicular to 垂直于
∪union of 并，合集
∩intersection of 交，通集
∫the integral of …的积分
∑(sigma) summation of 总和
° degree 度
′minute 分
″second 秒
＃number …号
℃Celsius system 摄氏度
＠at 单价
标点符号和运算符号
常用标点符号用法
句号 Period
用以表示一个句子的结束
Hockey is a popular sport in Canada.
The federal government is based in Ottawa.
用在缩写中
B.C. is the province located on the West Coast. Dr. Bethune was a Canadian who worked in China. The company is located at 888 Bay St. in Toronto.
It is 4:00 p.m. in Halifax right now.
问号 Question Mark [?]
在句子的结尾使用问号表示是直接疑问句：
How many provinces are there in Canada?
注意：在间接疑问句结尾不要加问号：
The teacher asked the class a question.
Do not ask me why.
叹号 Exclamation Mark [!]
在句子的结尾使用叹号表示惊讶、兴奋等情绪：
We won the Stanley Cup!
The forest is on fire!
逗号 Comma [,]
句子中的停顿
Therefore, we should write a letter to the prime minister. 在疑问句中引出说话人：
"I can come today," she said, "but not tomorrow."
排列三个或以上的名词：
Ontario, Quebec, and B.C. are the three biggest provinces. 引出定语从句
Emily Carr, who was born in 1871, was a great painter. 单引号 Apostrophe [']
表示所有
This is David's computer.
These are the player's things. (things that belong to the player)
Note: 对于复数形式的名词，只加'
These are the players' things. (things that belong to the players)
缩写I don't know how to fix it.
引号Quotation Marks ["]
直接引出某人说的话：
The prime minister said, "We will win the election."
"I can come today," she said, "but not tomorrow."
冒号Colon [:]
引出一系列名词
There are three positions in hockey: goalie, defence, and forward.
引出一个较长的引语
The prime minister said: "We will fight. We will not give up. We will win the next election."
分号Semicolon [;]
将两个相关的句子连接起来
The festival is very popular; people from all over the world visit each year.
和逗号一同使用引出一系列名词
The three biggest cities in Canada are Toronto, Ontario; Montreal, Quebec; and Vancouver, B.C. 破折号Dash [-]
在一个句子前作总结
Mild, wet, and cloudy - these are the characteristics of weather in Vancouver.
在一个句子的前面或后面加入额外的注释
The children - Pierre, Laura, and Ashley - went to the store. Most Canadians - but not all - voted in the last election.
表示某人在说话过程中被打断
The woman said, "I want to ask - " when the earthquake began to shake the room.
连字符Hyphen [-]
连接两个单词
sweet-smelling
fire-resistant
将前缀
anti-Canadian
non-contact
在数字中使用
one-quarter
twenty-three
加、减、乘、除的表示法
加、减、乘、除的表示法：
1．加：用and ,plus , added to 等词表示。
2 ＋ 4 ＝ 6 可译为：
Two and four is six .
Two plus four is equal to six .
Two added to four equals six .
Two and four makes six .
Two plus four will be six .
If you add two to four , you get six .
2．减：用minus, taken from, subtracted from 等表示。
8－3=可译为：
Eight minus three is five .
Eight minus three is equal to five .
Three taken from eight leaves five .
Three subtracted from eight leaves five .
Take three from eight and the remainder is five .
3．乘：用multiply···by···/ multiplied by / time 等表示。
3 × 5 = 15可译为：
Multiply three by five is (gives)fifteen .
Three multiplied by five is fifteen .
Multiply three by five , you get fifteen .
Three times five is (makes, will be , equals, is equal to ) fifteen . 4．除：用divide···by···/ divided by / divide···into··· / into 等表示。
24 ÷ 8 = 3 可译为：
Twenty-four divided by eight makes (is , equals ) three .
Twenty-four divided by eight is equal to three .
Eight into twenty-four goes three times .
Divide eight into twenty-four , and you get three .
Divide twenty-four by eight , and you get three .
度量衡分类
1. 国际制度的单位
国际制度（The International System，缩写为SI，是国际制度的法语名称）被1960年的第十一届大会用于度量衡。
公制的扩大和修改版本，即国际制度针对了现代科学附加的及更加正确的度量单位的需要。
国际制度的主要特点是采用了十进制法、字首体系、以不变的物理度量方式解释的标准。
2. 基本单位
国际制度有基本单位，由此衍生出此制度中的其他单位。
除千克以外，基本单位的标准以不变的且可再生的物理事件为解释。
例如，公尺被解释为光在真空中以每1/299,792,458秒的速度所穿越的距离。
千克的标准是指置于法国塞夫勒的国际度量及标准局的白金铱圆柱为准。
计量单位计量范畴符号
meter 公尺length 长度m
kilogram 千克mass 质量kg
second 秒time 时间s
ampere 安培 electric current 电流 A
kelvin 开temperature 温度K
mole 摩尔 amount of matter 数量mol
candela 烛光 luminous intensity 发光强度cd
3. 辅助单位
国际制度采用了两种辅助单位，其依据于抽象的几何概念而非物理标准。
计量单位计量范畴符号
radian 弧度 plane angles平面角rad
steradian 立体弧度solid angles立方角sr
4. 前缀
经由在单位名称前面加一前缀构成国际制度单位的倍数。
前缀通常按顺序从10的18次幂到10的-18次幂改变单位的量。
前缀符号乘法因数
exa-代表10的18次幂 E 10的18次幂 =1,000,000,000,000,000,000
peta-代表10的15次幂P 10的15次幂 =1,000,000,000,000,000
tera-代表"万亿" T 10的12次幂 =1,000,000,000,000
giga-代表"十亿" G 10的9次幂 =1,000,000,000
mega-代表"百万" M 10的6次幂 =1,000,000
kilo-代表"千" K 10的3次幂 =1,000
hecto-代表"百" h 10的2次幂 =100
deca-代表"十" da 10 = 10
deci-代表"十分之一" d 10的-1次幂 =0.1
centi-代表"百分之一" c 10的-2次幂 =0.01
milli-代表"千分之一" m 10的-3次幂 =0.001
micro-代表"百万分之一" μ10的-6次幂 =0.000,001
nano-代表"毫微" n 10的-9次幂 =0.000,000,001
pico-代表"万亿分之一" p 10的-12次幂 =0.000,000,000,001
femto-代表"千万亿分之一" f 10的 15次幂 =0.000,000,000,000,001 atto-代表"百亿亿分之一" a 10的 18次幂 =0.000,000,000,000,000,001
5. 附加单位
几个非国际制度的单位。
计量单位计量范畴符号
angstrom 埃(=10 -10米) length 长度 A
electron-volt 电子伏特(=0.160焦耳) energy 能量eV
hectare 公顷(=10,000平方米) land area 面积ha
liter 升(=1.0立方米) volume or capacity容积或容量l standard atmosphere 标准大气压(=101.3毫巴) pressure 压强atm
6. 导出单位
国际制度中大多数单位都是导出单位，即以基本单位和补充单位的方式加以解释的单位。
导出单位可分为两组──具有特定名称和符号的一组，不具有特定名称和符号的一组。
第一组，带有特定名称和符号的导出单位：
计量单位计量范畴符号
coulomb 库 electric charge 电量 C
farad 法拉 electric capacitance 电容 F
henry 亨利inductance 电感H
hertz 赫兹frequency 频率Hz
joule 焦耳 quantity of energy 能量J
lumen 流明flux of light 光通量lm
lux 勒克斯 illumination 照度lx
newton 牛顿force 力N
ohm 欧姆electric resistance 电阻Ω
pascal 帕斯卡pressure 压强Pa
tesla 特斯拉magnetic flux density 磁通量密度T
volt 伏特 voltage 电压V
watt 瓦特power 功率W
weber 韦伯 magnetic flux 磁通量Wb
第二组，无特定名称和符号的导出单位：
计量范畴推导方式
acceleration 加速度m/s2
angular acceleration 角加速度rad/s2 angular velocity 角速度rad/s
density 密度kg/m3
electric field strength 电场量V/m luminance 亮度cd/m2
magnetic field strength 磁场量A/m velocity 速度m/s
常用标点符号用法
常用缩略语表
．period 句号
，comma 逗号
：colon 冒号
；semicolon 分号
！ exclamation 惊叹号
？question mark 问号
￣ hyphen 连字符
' apostrophe 省略号；所有格符号— dash 破折号
‘’ single quotation marks 单引号“” double quotation marks 双引号
[] square brackets 方括号
《》 French quotes 法文引号；书名号
... ellipsis 省略号
¨ tandem colon 双点号
" ditto 同上
ǁparallel 双线号
／virgule 斜线号
＆ampersand = and
～swung dash 代字号
§ section ;
→arrow 箭号；参见号
＋plus 加号；正号
－minus 减号；负号
± plus or minus 正负号
× is multiplied by 乘号
÷ is divided by 除号
＝is equal to 等于号
≠ is not equal to 不等于号
≡is equivalent to 全等于号
≌is equal to or approximately equal to 等于或约等于号≈ is approximately equal to 约等于号
＜is less than 小于号
≮is not less than 不小于号
≯is not more than 不大于号
≤is less than or equal to小于或等于号≥is more than or equal to 大于或等于号％per cent 百分之…
‰ per mill 千分之…
∞infinity 无限大号
∝varies as 与…成比例
√(square) root 平方根
∵since ;
∴hence 所以
∷equals ,
∠angle 角
⌒semicircle 半圆
⊙circle 圆
○ circumference 圆周
πpi 圆周率
△triangle 三角形
⊥perpendicular to 垂直于
∪union of 并，合集
∩intersection of 交，通集
∫the integral of …的积分
∑(sigma) summation of 总和
° degree 度
′minute 分
″second 秒
＃number …号
℃Celsius system 摄氏度
＠at 单价
英语书信写作指导
—、书信写作要求
书信(Letter)一般可分为事务信件或公函(Business Letter or Offical Correspondence)以及私人信件
(Private Letter)两大类。
一般包括以下几个要点：
1）收信人的姓名和地址；
2）寄信人的姓名及其与收信人的关系；
3）寄信人的地址（有时可以省略）；
4）写信的时间；
5）信的内容。
1. 书信的格式
1）信头(Heading)；
2）称呼(Salutation)；
3）正文(Body of the letter)；
4）结束语(Complimentary close)；
5）签名(signature)。
2. 书信的种类
1）邀请信
邀请信有正式和非正式之分，也有介于两者之间者。
正式邀请信一般属于公函类，私人邀请信一般属于非正式文体。
邀请朋友、熟人参加某一聚会时，再词句上不一定多加斟酌，用词太正规倒显得关系不密切。
但是如果与被邀请人不太熟悉的话，最好用正式文体。
如虽认识但并不十分了解，文体可介于两个者之间。
由此可见，私人邀请究竟用什么文体，关键看与被邀请人之间的亲疏的程度。
邀请信要明确写出活动（是晚会、晚餐还是一般的聚会等）、活动的时间地点组织这项活动的理由，有时还应告诉对方可能出席的人，另外一般希望对方给予答复。
（1）非正式邀请信，如；
26 Coventry St.
London
Sept. 15th, 1999.
Dear Jack,
I am going to the cinema to see the Red River Valley and I have two tickets. Would you like to come? The film starts at 7:30 p.m. Maybe we can meet at the Covent Garden Station at 7:00 p.m. and have a drink before the film starts. Please phone me at home to let me know.
Looking forward to seeing you.
Love
Mary
这封信是写给朋友的，所以用语比较随便，比较口语化。
（2）正式邀请信，如：
Dear Ms. Gupta;
It’s our great pleasure to announce that Jan. 19th is the 3rd anniversary of the founding of our corporation. We have a small party as follows: 7:00p.m.,Jan. 19th, Room No.123, Kunlun Hotel. At this moment, we would like to express our sincere gratitude to our clients for both courtesy and support over the past three years. Please confirm if you plant to attend.
Yours Sincerely,
Lewis
这是一封正式邀请信，十分正规，无论从句式，还是用语都十分讲究。
(3) 介于正式和非正式之间的邀请信，如：
No.4 Middle School
Beijing 100034
April 29th,2000
Dear Miss Katherine,
I am very pleased to write to you. My name is Yu Hong and I am monitor of Class One, Grade Three of the No.2 Middle School of Ji'nan. Last year, you came here to give a speech, which was "Fast Reading". My classmates and I all thank you very much. We will have an English evening at 7:00--9:00 on the evening of May 4th in our classroom. Would you please come and attend the evening party? At the party, we will sing English songs, play games and so on. And we are anxious to invite you to come to sing us an English song. After that we can enjoy the music. We hope to see you soon.
Yours
Yu Hong
这封信是写给一位外籍教师的，这位外籍教师曾经到过这所学校，虽然作者认识，但并不十分了解。
2）感谢信
感谢信可分为感谢馈赠、感谢款待、感谢帮助、感谢送行和感谢探病等。
感谢信一般包括以下几点：
①对收信人的称谓；
②写信的目的；（Thank you for…）
③致谢并详述所收到的礼物或得到的帮助等；
④结尾及谦称。
如：
Dear Ms. Gupta:
How regretful I must leave you house. Thank you for the many good things you provided. The chess game, tennis match and Mr. Gupta's delicious dishes gave me lots of enjoyment. If you came to Beijing for any reason, please come to my family. The kids are looking forward to seeing Aunt Jean. I believe we will have a very happy time.
Yours Sincerely, Lewis
3)求职信
求职信属于公务信函，格式和用词比较规。
信的内容大体上分为三部分
①写信的目的，
②自我介绍，
③要求。
注意下面几点：
①写信的目的要直截了当地在信的开头提出。
②自我介绍部分主要介绍自己的学历、工作经历、解决问题的能力等等。
在行文、用词上要表现出自信、恳切的态度，语言简明扼要，突出介绍自己的优点，与众不同的特长或有利条件。
还要紧扣用人单位的需求，巧用词语，有国地说服对方，此职非你莫属。
③最后提出进一步联系的途径，如：时间、地点。
还可以主动提出接受面试或考核等。
④求职信在写作特点上主要用第一人称以及动词的一般现在时。
如：
Ms Li Ling
P.O.Box 231
Beijing
July 10,1999
Dear sir(s),
I have just read in the newspaper that a secretary of the English language in wanted in your company. I am therefore writing to you to introduce myself. I'd like to get the job. I am a girl college student of 22 years old. My name is Li Ling. I am studying in the language department. I can speak, read and write English very well. As a second language, I can read and speak a little French. I have some work experience as a typist in my spare time at school, and as a tourist guide during summer holidays. The bosses I worked for were all satisfied with my work. I am sure I'll satisfy you as well. You can get more information about my studies and work from the college. I am looking forward to visiting your office at any time for a talk or a test.
Faithfully
Li Ling
3)回信
写回信时应特别注意正确理解写信人的意图、所提问题、必须对写信人的问题给予明确的答复。
如下例：
No.1 Middle School of Nanjing,
Jiangsu, China
Jan.23rd, 2000
Dear Jack
Thanks for your letter. Yes, I have some difficulty in learning English. For example, I can't tell the difference between written English and spoken English. Sometimes I often make mistakes while speaking to others. I want to improve my spoken English. But I don't know how. Would you please give me some advice? As you say, it is really difficult to write toe Chinese characters, but don't worry about it. Have you considered doing plenty of practice? And I suggest you write them as much as possible. I think it will be of great help. I'm looking forward to hearing from you again. Best wishes.
Yours
Li Ling
原信中作者问到英语学习的情况，同时征求学习汉语的建议并谈到自己在学习汉语的过程中遇到的问题。
回信中作者对来信中的问题作了详细的回答并给出了建设性的建议。
英语日记写作指导
英文日记和汉语日记一样，是用来记叙一天中所发生的有意义的事情或对将来的打算等。
日记可分为记事、议论、描写及抒情等。
记事型是用英语记述当天自己生活学习中发生的事情。
议论型是对生活中的某一事情或情况现象谈自己的看法，发表议论。
描写型或抒情型，则是对某人物事物的特征做细致的描述，或针对某事物抒发自己的感情。
１．格式：
一般是在左上角记上当天日期，星期，时间的排列法与书信一致，星期写在日期之后；右上角写上当天的天气情况，表示天气情况的词一般是形容词，如：fine （晴朗的），cold （寒冷的），snowy（下雪），sunny（阳光充足的），rainy（下雨的），cloudy（阴天的）等。
日记的小标题写在下一行，也可省略不写。
２．时态：
写日记的时间一般是在下午、晚上，有时也可以在第二天补写。
因此，日记中所记述的事情通常发生在过去，常用一般过去时；但当记述天气、描写景色或展望未来时，可以用一般现在时或一般将来时。
写法大致和写汉语日记相同，都是在正文之前有日期、星期几及当天的天气情况。
注意内容表达要清楚连贯、准确。
