l do not think mr.black ------- a new flat 答案是need buy.我的问题是为什么不是needs to buy?needs buy 怎么知道这句话中need 是做实意动词？

l do not think mr.black ------- a new flat 答案是need buy.我的问题是为什么不是needs to buy?needs buy 怎么知道这句话中need 是做实意动词？
l do not think mr.black ------- a new flat 答案是need buy.我的问题是为什么不是needs to buy?
needs buy
怎么知道这句话中need 是做实意动词？

l do not think mr.black ------- a new flat 答案是need buy.我的问题是为什么不是needs to buy?needs buy 怎么知道这句话中need 是做实意动词？
needs to buy 也对
needs buy不对.
如果need后跟to do,那就是作实义动词.直接跟do,就是作情态动词

此时need为情态动词

need 做情态动词用的时候 直接+动词原形
做实意动词的时候 才+to do

need情态动词