1.average平均on（the） ~   

2.be aware of = realize意识到be sure一定要，肯定    He apologized to us for the mistake as soon as he was aware of it.    Be sure not to be late for the meeting.    I'm sure the play will be a great success.

3.back up支持    

4.background背景    

5.base ~…on…把…建立在…基础之上    His article is based on the research.    

6.bear忍受，容忍同义词：    endure tolerate stand put up with    She cannot bear to see the child in pains.    

7.do/try one's best    He said he would try his best to carry out the plan.

8.because连词：There will be no meeting because the manager will be on the vacation next week.    because of介词：His wedding will be put off because of his father's death.   

9.best make the ~ of很好地利用   

10.had better do最好You'd better finish reading the book in this week，since I'm going to return it to the library.    would rather do宁愿I'd rather go there myself.    

11.beyond超出…    The professor's lecture is beyond me/beyond my understanding （超出我的理解范围）。    The apple on the tree is beyond my reach（够不着）。    

12.Both…and…两者都either…or…或者…或者…    neither…。nor…。两者都不    

13.be bound to do注定…    You're bound to succeed as long as（只要）you keep on trying.    

14.break into闯入break out爆发break through突破break up（关系等）破裂    

15.catch one's breath    

16.call off=cancel取消call on=visit拜访call for请求，号召    The resident called for the people to fight against the invaders.   

17.care for关心，在乎take care保重take care of=look after照顾    

18.carry on继续carry out实施，执行    They decided to carry out the plan despite the opposition.   

19.case事实，实情；箱子；案例；病例    in case（of）以防，万一Take my umbrella in case it rains.    In most cases在大多数情况下    In no case决不in no way by no means    

20.catch up with赶上，保持一致keep up with keep pace with    

21.（be）in charge of 掌管，负责    take charge of 掌管，负责    charge…for… 开价，要价The short man there is in charge of our company.    The hotel charges $100 for a double room.    

22.challenge 挑战    

23.change 零钱（n.）换零钱（v.）    

24.comfort v.& n安慰；舒适，舒服    comfortable舒服的，舒适的    

25.have…in common有共同之处    Although they are twins they have little in common.   

26.communicate 传播，交流    

27.compare…to…把…比作…。    compare…with…把…与…相比    Poets like comparing their lovers to red roses.    Compared with brain，computer still has some shortcomings.    

28.complain of/about抱怨   

29.be made up of由…。组成be composed of consist of 

30.concentrate on集中注意力于be engaged in