请问句中的‘That's That's how I know the job must have been done.

请问句中的‘That's That's how I know the job must have been done.
请问句中的‘That's
That's how I know the job must have been done.

请问句中的‘That's That's how I know the job must have been done.
那就是我怎么知道这个工作必须做的原因.

这就是我怎样...