请教：高分语法中一道语法题

ryanxiao_la

Human being have thirty-three or thirty-four vertebrae, but a snake may have  as many as three hundred.

Answer: A（我选C） 改为beings, 解释原因为谓语have是复数，主语应保持一致，故改为human beings

但我不解的是：同理，后半段but分句主语是a snake（单数）为什么其谓语不用has，而是may have as many as …?

maryann

情态动词后用动词原型