---It’s difficult for the villagers to c
问题:
---It’s difficult for the villagers to cross the river.
---I think a bridge______ over the river.
A.should be built
B.is being built
C.has been built
D.was built
---It’s difficult for the villagers to cross the river.
---I think a bridge______ over the river.
A.should be built
B.is being built
C.has been built
D.was built