This passage supports the belief that ______.A.exact reasons for migration are not knownB.birds migrate because of changes in temperatureC.the ancestral home of all birds was the tropicsD.glaciers caused birds to migrate
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She wasn't feeling very well; otherwise, she ______ the meeting so early.A.wouldn't leave
Bob: Can I help with your luggage?Mary: ______A.No, thanks. I can manage itB.No, many thanks. I can doC.No, not necessary. Thank you anywayD.No, you needn't. Thank you anyway
According to the theory of photo-periodism, ______.A.birds should migrate in the middle of
Which of the following is true?A.The international service in August would be as much as in July.B.The flow of international passengers will be more than that in July.C.The airport will provide less service than in July.D.The flow of international passengers will be more than that in usual time.