問題詳情
75. In recent years, there has been an increase in
environmental disasters, and scientists are unsure _____.
(A) what contributes to them it is
(B) what is contributing to them
(C)what the contributions to them is
(D) who contributes to them it is
參考答案
答案：B
統計：A:0,B:14,C:4,D:0,E:0
難度：計算中