情态动词MUST的用法及肯定回答和否定回答

Must用法全接触
一、表“必须”.
You must talk to them about their study.你必须同他们谈谈关于他们学习的事.
二.在否定结构中表不许.
You mustn't leave here.你不能离开这儿.
三.表坚定的建议.
You must come and see us as soon as you get to Shanghai.一到上海你得马上来看我们.
四.表推测,暗含有很大的可能性,用在肯定句.
He must be ill.He looks so pale.他肯定是病了.他的脸色那么苍白.
注意：
may 暗含的可能性较小.must 暗含的可能性较大.否定的猜测用can't
The baby can't be ill.He is so active.那宝宝不大可能是病了.他那么活跃.
五.关于must的简短回答：
Must I clean the dining room at once?我必须马上打扫膳厅吗?
Yes,you must.是的.
No,you needn't.不必马上打扫.（No,you don't have to.）