请问为什么选A Tom is very tired ,He needs ( ) a good sleep.A :to h

need可作实义动词或情态动词
当它做情态动词时,用法与can,could,will等词的用法相同,则原句就为
He need have a good sleep.
而原句中的need后加了s,为单三形式,说明它是作为实义动词使用的,和一般动词的用法一样
则为He needs to have a good sleep.
中间加to是为了连接两个动词