问题补充：
The workers were made for ten 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：D 考查不带to的不定式，即使役动词。使役动词make的用法是：make sb. do sth.，在被动语态中，不定式to必须加上，即sb. be made to do sth.。故选D。“这些工人被迫一天工作10个小时。”
