题目内容：

---People find it hard to get across the river.---I think at least two bridges _____ over it.A.need   B.are needing   C.will need   D.are needed

优质解答

D 这里应该是被动的,need做实意动词“需要”,over 是介词,意为“穿过,跨过”
人们发现很难跨过这条河流.我认为至少需要两座桥才能过去.