. a

1.[c][u]英语字母表的第 1 个字母the first letter of the English alphabet

3.[c][u]（学业成绩）第一等，优，甲the highest mark/grade that a student can get for a piece of work or course of study

4.[u]（表示两个或更多可能性中的）第一个used to represent the first of two or more possibilities

5.[u]（代表一个假设的或不指名的人）甲used to represent a person, for example in an imagined situation or to hide their identity

from A to B

从一地到另一地from one place to another

from A to Z

从头到尾；彻底地；完全including everything there is to know about sth

1.A 级公路，干线公路（英国公路代号，后接数字）used in Britain before a number to refer to a particular important road

2.（除美国外，用于数字前表示标准纸张尺寸） A …号纸（尺寸）used (but not in the US) before numbers which show standard metric sizes of paper

1.英文字母表的第一字母

2.【数学】第一已知数

3.(学业成绩的)优等

4.表示“第一”的符号

5.腺苷

6.吸光率

1.〔普通可数名词第一次提到时,冠以不定冠词主要表示类别,有时则兼含“一”的概念〕

1.〔在数量概念上,说明表示时间,距离,重量及数目的名词〕一

2.〔与数量形容词,数词等连用而表示一个整体单位〕

3.〔与某些复数名词连用而仍表示一个单位〕

4.〔与序数词或形容词最高级结合共同限定所修饰的名词〕

5.〔表示同类事物中的代表〕任何一个[种]

6.同一的,相同的

7.一(副)

8.〔抽象名词用作普通名词,表示类别,例证〕

9.〔用于专有名词前,以整体概括个体,表示类似的一个或某一个〕

10.每(...),在...内,按(...而论),换(得)

11.〔口语〕一客

1.acceleration

2.activity

3.used to refer to the first vertical row of squares from the left on a chessboard

4.adenine

5.ampere

6.mass number

7.10

8.angstrom

9.used to indicate a main road other than a motorway

10.the first letter of the English alphabet, representing a vowel sound

11.a written representation of the letter "a"

12.the sixth note of a scale in C major. The A above middle C is often used to tune instruments and is standardized at a frequency of 440 hertz.

13.a string, key, or pipe tuned to produce the note A

14.a scale or key that starts on the note A

15.a graphic representation of the tone of A

16.the highest grade in a series, e.g. a top grade for academic work

17.a human blood type of the ABO system, containing the A antigen.

18.something shaped like a letter 'A'

19.in the market research system that classifies people according to their occupation, somebody in a senior management, professional, or administrative position

20.the sixth note in the musical scaleNDV> of C majorNDV>

21.a mark that a teacher gives to a student’s work to show that it is excellent

22.a common blood groupNDV> in the abo systemNDV>

1.used before a noun to indicate that somebody or something has some of the same qualities as the person or thing mentioned

2.used instead of "one" with words of measurement

3.in each or in every

4.used to indicate somebody not personally known, but known of

5.used in negative structures to emphasize a complete absence of something

1.used before a noun to indicate that somebody or something has some of the same qualities as the person or thing mentioned

2.used instead of 'one' with words of measurement

3.in each or in every

4.used to indicate somebody not personally known, but known of

5.used in negative structures to emphasize a complete absence of something

6.used when you are mentioning a person or a thing for the first time, or when the person listening to you does not already know about them

7.used when you mean any person or thing of a particular type, but you are not referring to a specific one

8.used when you say what class, type, or group someone or something belongs to, or what job someone has

9.used before a singular noun that represents every person or thing of a particular type

10.used when you are referring to a person or thing as one of several people or things of this type

11.used in expressions of quantity such as “a lot,” “a few,” or “a great deal”

12.used in numbers and measurements to mean “one,” as in “a thousand” or “an hour”

13.used in phrases showing how much something costs, how often it happens, how fast it goes, etc.

14.used before a noun that means a substance, product, food, etc. when referring to a particular type of it

15.used before the name of some drinks to mean a cup or glass of that drink

16.used before a noun that means a particular quality or feeling when the quality or feeling is described in some way

17.used before a noun that is formed from a verb and means a single action of that verb

18.used before a noun that expresses your feelings about a situation

19.used before the name of a particular day, season, or holiday to mean one particular Tuesday, summer, Christmas, etc.

20.used before a person’s name when you do not know anything about them

21.about

22.academy

23.acre

24.adult

25.answer

26.arrives

27.amp