一. 介词加关系代词
注意1. 含介词的引导词,其介词可放在引导词whom,
which前或在从句原来的位置上.介词不提前,
其在从句中作宾语的引导词who, whom, that,
which可省.
但含有介词的短语动词一般不能拆开,如
look after, be made of, take part in, look forward to等.