don't need to do 与needn't do 有什么区别?还有needn't 是否只能用于一般现在时?

Question

don't need to do 与needn't do 有什么区别?
还有needn't 是否只能用于一般现在时?

Answer 1

don't need to do 与needn't do 有什么区别?
有一定的区别：
don't need to do 这里need是个行为动词,而needn't中的need是情态动词；
needn't应该相当于don't have to 更好
还有needn't 是否只能用于一般现在时?
是的,一般只用于一般现在时,但在宾语从句中也可表示过去或将来（不太常见）.