We all know( ).括号填1when does the class begin 2when does the class begins 3when the class begin选

问题描述:

We all know( ).括号填1when does the class begin 2when does the class begins 3when the class begin选

不是疑问句不需要倒装,class是单三;
应该这样说才对:
We all know when the class begins.