They are going to have the serviceman an electric fan in the office tomorrow.A. installB.

问题补充：

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

答案：

(答案→)A. install

B. to install

C. to be installed

D. installed

解析：在have sb. do sth.结构中 do sth.做宾语 the serviceman的补足语，和 serviceman构成了逻辑上的主语和谓语的关系，表示叫某人做某事。