I didn't expect that so many people to join in the work.A. had offeredB. were offeredC. w

问题补充：

I didn expect that so many people to join in the work.

A. had offered

B. were offered

C. would offer

D. used to offer

答案：

A. had offered

B. were offered

(答案→)C. would offer

D. used to offer

解析：would offer to…主动提出,这里would 表示意愿.