C. could drop D. ought to have dropped 10、You ___ not have seen her yesterday for she was abroad. A. must B. should C. could D. would 11、You could have done much better yesterday. Why ___? A. didn't you B. couldn't you C. hadn't you D. shouldn't ...
1)can could 表示能力;可能(过去时用could), 只用于现在式和过去式(could)。be able to可以用于各种时态。They will be able to tell you the news soon.他很快就能告诉你消息了。 2)只用be able to a. 位于助动词后。 b. 情态动词后。 c. 表示过去某时刻动作时。
A. must B. should C. could D. would 11、You could have done much better yesterday. Why ___? A. didn’t you B. couldn’t you C. hadn’t you D. shouldn’t you 12、“That latest car must have cost you a pretty penny.”“Oh, no ,___.” A. it didn...
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