28666578
幼苗
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用be to +动词原形表示职责、义务、意图、约定、可能性等.如:①You are to be back by nine o'clock.到九点你就得回来.②We are to meet at the schoolgate.我们要在校门口见面.注意:be to do还可以表示注定要发生某事.否定:not to be,疑问:be sb to do用be able to表示能力,译能否定:be not able to do疑问:be sb able to do
1年前
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