She needs to eat healthy food.He needn't hand in his homework today.(看问题补充）
问题描述：
She needs to eat healthy food.He needn't hand in his homework today.(看问题补充）
为什么上一句要加to,下一句不要加,eat和hand in不都是动词吗,怎样区分need到底是实义动词还是情态动词?
答
need作动词时不论是实意动词还是情态动词,意思都是一样的,需要怎么样.
这里你如果无法判断后面要不要to,可以看need的词型.
前一句是needs,说明是实意动词,因为情态动词是没有单复数形势变化的,只能肯定否定.所以后面就用need相应的搭配need to do sth.
后一句是needn't,说明是情态动词,因为如果是实意动词的话,否定就只能用he doesn't need to了,只有在情态动词的时候,才能用needn't的否定方法,所以后面就直接家动词原形.