61. on the average (=on average, on an average) 平均
62. (be) aware of (=be conscious of , having knowledge or consciousness)意识到,知道.
63. at the back of (=behind) 在…后面
64. 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.
65. 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
66. turn one’s back on sb. (=turn away from sb. in an impolite way) 不理睬(某人),背弃,抛弃
67. behind one’s back 背着某人(说坏话)
68. be based on upon 基于
69. on the basis of 根据…, 在…基础上
70. beat…at 在…运动项目上打赢
71. begin with 以…开始. to begin with (=first of all) 首先, 第一(经常用于开始语)
72. on behalf of (=as the representative of) 以…名义
73. believe in(=have faith or trust in; consider sth.sb. to be true) 相信,依赖,信仰.
74. benefit (from) 受益,得到好处.
75. for the benefit of 为了…的利益(好处)