1、情态动词后接动词原形,没有人称和数的变化,不能单独作谓语,与后面的动词共同作谓语,其否定形式在后面直接加not。2、表示能力(会)和允许(可以)。构成疑问句时,需把can移到句首。肯定回答为Yes,主语+can。否定回答为No,主语+can't。3、表示允许(可以)。其否定回答用can't或mustn't或may not。4、表示必须,其否定形式mustn't表示禁止(不准;不允许)。5、I can't swim.Can you swim?
Don't worry.You can return this book to me tomorrow.
You are here in the library. You...
用适当的情态动词填空。1.can2.can3.mustn't4.must5.must6.can7.can8.can9.must10.may11.must12.may13.can14.must needn't can15.can't1.have you prepared for this trip...