求英语达人告诉我答案以及为什么选这个答案.要详细一点.Before the first non-stop flight was made in 1949,it_____necessary for all planes to land for refueling.A.would be B.has been.C.had been D.would have been
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![求英语达人告诉我答案以及为什么选这个答案.要详细一点.Before the first non-stop flight was made in 1949,it_____necessary for all planes to land for refueling.A.would be B.has been.C.had been D.would have been](/uploads/image/z/5795645-5-5.jpg?t=%E6%B1%82%E8%8B%B1%E8%AF%AD%E8%BE%BE%E4%BA%BA%E5%91%8A%E8%AF%89%E6%88%91%E7%AD%94%E6%A1%88%E4%BB%A5%E5%8F%8A%E4%B8%BA%E4%BB%80%E4%B9%88%E9%80%89%E8%BF%99%E4%B8%AA%E7%AD%94%E6%A1%88.%E8%A6%81%E8%AF%A6%E7%BB%86%E4%B8%80%E7%82%B9.Before+the+first+non-stop+flight+was+made+in+1949%2Cit_____necessary+for+all+planes+to+land+for+refueling.A.would+be+B.has+been.C.had+been+D.would+have+been)
求英语达人告诉我答案以及为什么选这个答案.要详细一点.Before the first non-stop flight was made in 1949,it_____necessary for all planes to land for refueling.A.would be B.has been.C.had been D.would have been
求英语达人告诉我答案以及为什么选这个答案.要详细一点.
Before the first non-stop flight was made in 1949,it_____necessary for all planes to land for refueling.
A.would be B.has been.C.had been D.would have been求英语达人告诉我答案以及为什么选这个答案.要详细一点.Before the first non-stop flight was made in 1949,it_____necessary for all planes to land for refueling.A.would be B.has been.C.had been D.would have been
C.had been
解析:在过去的某个时间段( the first non-stop flight was made in 1949)之前,发生的事情(all planes to land for refueling.),即本题考察的是 过去的过去 应该用什么时态
A.将来式 .显然不符合
B.现在完成时.现在完成时强调的是过去的事情延续到现在,对现在产生影响,此题明显看 出于现在没有什么关系,不选.
C.过去完成时.强调发生的动作对过的某个时间(1949)产生的影响,符合.
D.一般用于虚拟语气.与此题不符(虚拟语气一般是假设,题中句子只是一般的陈述,没有假设成分),故不选.C had been
前面有了before,之前,而在过去式之前发生的事情就要加have/had(过去完成时)
而would代表没有发生但会发生的事情
但是后半句描述的事情已经发生了,就不能用wouldC,根据题意选择过去完成时