【例题】—I think Miss Gao must be in the library. She said she would go there. —No. She __be there， I have just been there. A.can’t B.mustn’t C.needn’t D.wouldn’t。
must，mustn't表示命令、禁止语气较强。e.g.The children must be back by 4 o'clock.You mustn't play football in the street. It's dangerous.
这篇文章的作业，知识点就是前面的情态动词相关文章，这里给出链接，方便随时查看，当情态动词遇上时态“我可能已经爱上你了”怎么说？‘提建议请求’用哪个？will,would,can,could,may,might?英语中表示‘推测’的情态动词-may?might?could?用哪个？
