英语：What are on show in the museum?-Some photos _ by the children of Yushu,Qinghai.A.have.
-What are on show in the museum?
-Some photos _ by the children of Yushu,Qinghai.
A.have been taken B.were taken C.are taken D.taken
为什么选D,不选C呢?
你们都没有说，为什么不选C啊.....