It must be a thief broke the glass.

问题描述:

It must be a thief broke the glass.

是吧 我觉得应该是
It must be a thief who broke the glass.
凭的语感啊,如果硬是不确定 问老师也可以呀

It must be a thief who broke the glass.

是.
It must be a thief who broke the glass.
这是个定语从句,必须由指示人的who来带领.