1. at, in, on 表示地点的用法区别. 2. at, in 表示时间的用法区别.
3. besides, except, except for 的用法区别. 4. 乘坐交通工具的介词使用.
5. to 后面跟什么?
come to be used to used to refer to speak to
give one's life to look forward to prefer to pretend to be worthy to
6. 介词省略的问题.
A) 动名词前的介词省略. B) 间接宾语前的介词省略.
