—It’s difficult for the village children to cross the river to get to school. We think a b

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。