1. on the average (=on average, on an average) 平均 2. (be) aware of (=be conscious of , having knowledge or consciousness)意识到,知道. 3. at the back of (=behind) 在…后面 4. in the back of 在…后部(里面). on the back of 在…后部(外面). be on one’s back(=be ill in bed) 卧病不起. 5. at one’s back(=supporting or favoring sb.) 支持,维护. have sb. at one ’s back 有…支持, 有…作后台 6. turn one’s back on sb. (=turn away from sb. in an impolite way) 不理睬(某人),背弃,抛弃 7. behind one’s back 背着某人(说坏话) 8. be based on upon 基于 9. on the basis of 根据…, 在…基础上 10. beat…at 在…运动项目上打赢 11. begin with 以…开始. to begin with (=first of all) 首先, 第一(经常用于开始语) 12. on behalf of (=as the representative of) 以…名义 13. believe in(=have faith or trust in. consider sth.sb. to be true) 相信,依赖,信仰. 14. benefit (from) 受益,得到好处. 15. for the benefit of 为了…的利益(好处) 16. for the better 好转 17. get the better of (=defeat sb.) 打败, 胜过. 18. by birth 在出生上,论出身,按血统 at birth 在出生时. give birth to 出生 19. blame sb. for sth. 因…责备某人 . blame sth. on sb. 把…推在某人身上 20. in blossom开花(指树木) be in blossom开花(强调状态) come into blossom开花(强调动作)