on the average (=on average， on an average)平均
(be) aware of (=be conscious of ， having knowledge or consciousness)意识到，知道。
at the back of (=behind)在…后面
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。
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
turn one's back on sb. (=turn away from sb. in an impolite way)不理睬(某人)，背弃，抛弃
behind one's back背着某人(说坏话)
be based on / upon基于
on the basis of根据…，在…基础上
beat…at在…运动项目上打赢
发表于 2016-8-9 16:26:39