【英语】Is everyone (having/has) a good time in the classroom?如题,括号内应选哪一个,并求简单的讲解,

问题描述:

【英语】Is everyone (having/has) a good time in the classroom?
如题,括号内应选哪一个,并求简单的讲解,

填having,句式是be ing,现在进行时.