题目内容
______ it have been the failure to pick up directions from the ground control that caused the air crash?
| A.Must | B.Could | C.Would | D.Should |
B
解析
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题目内容
______ it have been the failure to pick up directions from the ground control that caused the air crash?
| A.Must | B.Could | C.Would | D.Should |
B
解析