can't ,一般情况下只当做情态动词来用,有以下用法：
an't的美式发音是[kænt]，英式发音是[kɑ:nt]。can't用法是后加动词原形。
解释：禁不住 ; 不得不 ; 不能 ; 不足
can't 为短语，不省略后为 can not.或cannot，后加动词原形
表能力来讲,can't swim
表能够来讲,“不能”you can't do that
表猜测,“不可能”套盒pencil can't be lisa's,she is not here.
won't,当做助动词来讲
英 [wəʊnt] 美 [woʊnt]
解释：将不,不会(=will not)
将来时表将来 I won't go with you.
当做情态动词来用
表个人意愿,“不愿,不想”I won't make breakfast for him.
当做强调词来用I won't break up with her.
例句：
His parents won't allow him to stay out late.\x09
他的父母不会允许他在外待得很晚.
I won't encroach on your time any longer.
我不会再占用你的时间了.
I won't be finished for another hour.
我还得一小时以后才能完成.
Fretting about it won't help.
苦恼于事无补.
So you won't be coming tonight,huh?
那么你今晚就不来了吗,