--What are on show in the museum?--Some photos ___ by African children.

问题描述:

--What are on show in the museum?--Some photos ___ by African children.
A.are taken B.were taken C.taken D.have been taken
B C D应选哪一个,

选择C- What are on show in the museum?- Some photos taken by African children.用一个过去分词短语 taken by African children 做some photos的后置定语.为什么不用were taken 和have been taken,以及A中的are t...