The machine has been made easier for it.A. to operateB. operatedC. being operatedD. to be

问题补充：

The machine has been made easier for it.

A. to operate

B. operated

C. being operated

D. to be operated

答案：

A. to operate

B. operated

C. being operated

(答案→)D. to be operated

解析：考察不定式的复合结构。不定式的复合结构：For sb to do sth；本题从语义上来说又是被动语态，故D正确。