题目内容
The scientist __________ the experiment for half a year, but he _______ yet.
| A.made; didn’t succeed | B.made; hasn’t succeeded |
| C.was making; didn’t succeed | D.has been making; hasn’t succeeded |
D
解析
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题目内容
The scientist __________ the experiment for half a year, but he _______ yet.
| A.made; didn’t succeed | B.made; hasn’t succeeded |
| C.was making; didn’t succeed | D.has been making; hasn’t succeeded |
D
解析