問題詳情
44.The research is so designed that once ______ nothing can be done to change it.
(A) begins
(B) having begun
(C) beginning
(D) begun
參考答案
答案：D
難度：困難0.216495
統計：A(30),B(10),C(24),D(21),E(0)
用户評論
【Mark Tsai】評論
...that once it is begun- ...that once begunbegin不能用has begun