are going to have the service man _ an eletric fan

题目

are going to have the service man _ an eletric fan
They are going to have the service man _ an eletric fan in the office tomorrow.
A.install
B.to install
C.to be installed
D.installed
想问问这题答案为什么是A,我根据have sb done选了D

答案

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.