81. in the back of在...后面 支持, 主使

a) Actor Hugh Grant was caught with his pants down when he was having sex with a prostitute in the back of his car.

82. on the back of 在…后部(外面);

a) A guy is reading his paper when his wife walks up behind him and smacks him on the back of the head with a frying pan.

83. be on one's back(=be ill in bed) 卧床

a) He lay on his back, with his hands crossed under his head.他仰面躺着,头枕着手。

84. at one's back(=supporting or favoring sb) 支持

a) Don't talk about other's at his

back.

b) A:Tom should learn to look after himself.

c) B:Yeah,he can't always have us at his back.

85. have sb at one's back 有…支持, 有…作后台

86. behind one's back 背着某人(说坏话)

a) Don't speak evil of a man behind his back．

b) 不要在背后说人坏话。

87. turn one's back on sb (=close one's eye to sb) 不理睬(某人),背弃,抛弃

a) If the world turns its back on you, you turn your back on the world.

88. be based on / upon 基于

a) This news report is based entirely on fact.

b) 这篇新闻报导是完全根据实际情况写成的。

89. on the basis of 根据…, 在…基础上

a) On the basis of the above results, we may establish attractor viewpoint of process of the long-range atmosphere and climate.

90. begin with 以…开始

a) Knowledge begin with practice. 认识从实践开始。