请赐教 I needn't 和 I don't need的区别?

问题描述:

请赐教 I needn't 和 I don't need的区别?
可否举例说明?

I needn't do sth
I don't need to do sth.
这两个短语意思相近都有不必要的意思,可以换用,但是need后面有not的话是情态动词,后面用动词原形.而don't need后面跟不定式.