4.They are going to have the serviceman ___ an electric fan in the office tomorrow.

问题描述:

4.They are going to have the serviceman ___ an electric fan in the office tomorrow.
A.install
B.to install
C.to be installed
D.installed
为什么不是其他选项,尤其是B,
请详细说明,顺便说一下have的用法.

记住这个句型 have sb DO sth 是让某人做某事,因为DO 部分要用动词原型,而不是不定式所以不能选B .如果DO 部分用过去分词,表示让某事被做.如:have an electric fan installed.这就是have sth DONE 句型.所以不能选D.
have sb DO sth 是让某人做某事
have sth DONE 让某事被做
have to do sth 表示必须做某事
have done sth 是现在完成时的基本结构.