12Unit 3 Language in use祈使句结构如下: (Please) + do sth
(Please) + Don’t do sth
肯定:否定:DO ,可以放在动词前,为加强语气用
如: Do come in, please
Do listen to me, please
Do open the door, please
一、我们已经学习的表推测的情态动词有: must/can/could/may/might二、表推测的三种句式:1
在肯定句中一般用 must , can/could , may/might ,程度逐渐减弱
He must/may/might know the answer to this question
You have worked all this week
You must be tired
在否定句中用 can’t/couldn’t ( 不可能 ) , may not/ might not( 可能不 )
It can’t /couldn’t be the headmaster
He has gone to America
He may not/might not know the scientist
在疑问句中,一般只使用 can/could
Could he have finished the task
Can he be at home now
Language practice That could be harmful
Betty, you must know
Stay away from windows and heavy furniture
Do not stand near street lights or under p