问题补充:
The research is so designed that once nothing can be done to change it.
A. begins
B. having begun
C. beginning
D. begun
答案:
A. begins
B. having begun
C. beginning
(答案→)D. begun
解析:答案选D,可视为once it is begun之省略。
【标签】省略
时间:2019-02-22 09:12:59
The research is so designed that once nothing can be done to change it.
A. begins
B. having begun
C. beginning
D. begun
A. begins
B. having begun
C. beginning
(答案→)D. begun
解析:答案选D,可视为once it is begun之省略。
【标签】省略