因为特殊疑问句是将特殊疑问词提前.
what's yout name?——正过来说是,your name is what,正常的“主系表”结构
what class/grade are you in——同样的,you are in what class/grade
如果是what's, 那就是 you are in what's class/grade . 同一个句子里面出现两个动词是错误的我是问为什么在前一个是用what's，后一句是用what后面如果是用“what's ”就一句话里两个动词了