能否解释一下musn't,needn't ,don't have to,can't ,couldn't的区别?
3个回答

musn't,禁止.语气强硬.要注意和needn't区别

needn't= don't have to,不必,不需要

can't 不能,不可以

couldn't:第一个是can't 的过去式,第二个是 语气委婉时的用法.

may,可能.表推测

might.1.may过去式,2.可能,表推测,可能性较大

另:当用must引导一般疑问句时,肯定回答:yes,you must.否定的绝对绝对绝对不能用no,you mustn't,得用no,you needn't 或者no ,you don't have to.

这是个常考点,也是易错点.你可以想他的意思来理解.

for example:

Must i wash the dishes?

yes ,you must.

no ,you need't.

问.我必须洗盘子吗?

肯.是的,你必须.

否.不是,你不需要.你不能说,不行,你禁止洗盘子.语气上就说不通.