he couldn't persuade her to change her mind,no matter how hard he ___ try

问题描述:

he couldn't persuade her to change her mind,no matter how hard he ___ try
a.could b.might c.may
为什么选B?而A,C不对?

首先应使用过去时.然后can往往指一个人做某件事情的能力,如I can ride a bike.I can sing.I can dance.这里try并不是一种能力.只是普通的可以的意思.