问题补充:
—It’s difficult for the village children to cross the river to get to school. We think a bridgeover the river.
A. was built
B. should be built
C. has been built
D. is being built
答案:
A. was built
(答案→)B. should be built
C. has been built
D. is being built
解析:句意:对于村里的孩子过河去上学是困难的。我认为在河上应该建一座桥。桥是动作的承受者,作主语,故用被动结构。含有情态动词的被动结构:情态动词+ be +done. 故选B。