The workers were made twelve hours a day.A. workB. to workC. workedD. working

问题补充：

The workers were made twelve hours a day.

A. work

B. to work

C. worked

D. working

答案：

A. work

(答案→)B. to work

C. worked

D. working

解析：这些工人每天被迫工作十二个小时。make sb. do sth.让某人做某事，其中的to是省略掉的， 但用于被动的时候需要将to还原，也就是： … be made to do，故选B。