“We'd better hurry or we'll be late for the exhibit.” “No, we won't. The museum doesn't even open ____ another hour.” A. during B. for C. in D. at(TOEFL)
书上给的答案是 B(for)。但我无论如何也不能理解这里为什么要用 for, 而不用 in? 我怀疑书上的答案有误。
in 常常用来表示将来时间的“……之后”“……之内”。一般用在肯定句中：
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I shall come round in a day or two. (Voynich) 我一两天后就回来。
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I'll come in an hour. 我一小时后回来。
for 也可以用来表示将来时间的“……之后”“……之内”。但是，只能用在否定句中：
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The sun will not rise for about a quarter of an hour. 太阳不会在一刻钟内升起(太阳大约一刻钟后升起)。
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We needn't get ready yet; the guests shouldn't come for another hour. (LDCE) 我们用不着准备好;客人在一小时内还来不了。
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Our plane does not take off for another five minutes. 我们的飞机不会在 5 分钟之内起飞。
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He will not be well for some time yet. 他过一些日子才能恢复健康。
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The picture wouldn't end for another half hour. (EED) 电影在半小时之内不会结束。in/for²
I ____ there in three years. A. went B. have been C. haven't been D. was
这道试题中的 in three years 是否应改为 for three years? 本题答案为 C, 为什么不能选 B (have been) 呢?
除 for 之外, in 也可以用来表示持续时间, 尤其是在美国英语中。但是, in 与 for 不同, 常用在否定句中:
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I haven't done that in years. (CGEL) 多年来我都不干这个了。
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To visit some one you haven't seen in a long time is to look him up. (TOEFL) 访问你长久没有见到的人, 就是拜访他。
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She hasn't seen her daughter in three months. 她三个月没有见到她女儿了。
因此，在上道试题中不能选 B。