HOW much revision do you before an exam?这句话是什么意思

问题描述:

HOW much revision do you before an exam?这句话是什么意思

这个句子有语法错误,do you ...后面没有实义动词(即谓语缺一半)
应该是:How much revision do you (have) before an exam?
意思是:你们考试前会有多少复习?