The children were made 12 hours a day.A. workB. workedC. workingD. to work

问题补充：

The children were made 12 hours a day.

A. work

B. worked

C. working

D. to work

答案：

A. work

B. worked

C. working

(答案→)D. to work

解析：在主动语态中，make sb do sth，而在被动语态中，被省略的to 要加上去，故选D