题目内容
—I haven't heard from my sister since last month .
—Don't worry, Charlie. Letters from the United States ________be slow sometimes.
[ ]
A.need to
B.should
C.can
D.ought to
答案:C
解析:
解析:
|
导解:can表示理论上、习惯上的“可能会,有时会”. |
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