Dinosaurs have been extinct from the earth,never__again A.seen B.being seen C.to be seenD.having been seen为什么选C
问题描述：
Dinosaurs have been extinct from the earth,never__again A.seen B.being seen C.to be seen
D.having been seen
为什么选C
答
楼上已解
答
同样表被动,B表动作正进行,C一般表将来