49. on behalf of (=as the representative of)　 以……名义

On behalf of my colleagues and myself I thank you. 我代表我的同事和我本人向你表示感谢。

48. begin with 以……开始. to begin with (=first of all) 首先, 第一(经常用于开始语)

I have to begin with an apology. 我得首先表示歉意。

To begin with, she is too young for that kind of job. 首先，她做这种工作年纪还太轻。

47. be based on / upon 基于

Judgment should be based on facts, not on hearsay. 判断应该以事实为依据，而不应该依靠道听途说。

46. (be) aware of (=be conscious of , having knowledge or consciousness)意识到,知道.

He is not aware of his danger. 他没有意识到自己有危险。

45. on the average (=on average, on an average) 平均

On the average, there are 300 tourists a week. 每星期平均有300游客。

44. attribute…to…(=to believe sth. to be the result of…)把……归因于……, 认为……是……的结果

They attribute their success to their teacher’s encouragement. 他们把成功归因于老师的鼓励。

43. make an attempt at doing sth. (to do sth.) 试图做……

Before they fled the country, the enemy vainly made at attempted at destroying all the factories. 敌人在逃往国外前，妄图把所有工厂都毁掉。

42. assure sb. of sth. (=try to cause to believe or trust in sth.) 向……保证, 使……确信.

We book early to assure ourselves of seats. 我们及早订票以确保有座。

41. be ashamed of (=feel shame, guilt or sorrow because of　 sth. done) 以……为羞耻

You should be ashamed of what you have done. 你应为自己所做的事感到羞愧。

40. arrive on 到达; arrive at 到达某地(小地方);得出,作出;　 arrive in 到达某地(大地方);

You must arrive at the airport two hours early. 你必须提前两小时到达机场。

Flight number BA 4793 will arrive in London at 16:50. 英国航空公司4793号班机于16时50分抵达伦敦.