問題詳情
17. Only in recent years have people become aware of the importance of environmental protection
and _____ various measures to prevent pollution from worsening.
(A) do they begin to take
(B) they begin to take
(C) began to take
(D) begun to take
參考答案
答案：D
統計：A:21,B:12,C:19,D:62,E:0
難度：適中
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