They___the computer.A.don't need buy B.needn't to buy C.don't need to buy D.don't need buying

问题描述:

They___the computer.A.don't need buy B.needn't to buy C.don't need to buy D.don't need buying
为啥?

答案选C
need作实意动词的时候是:don't need to buy
作情态动词的时候是:needn't buy