They ( )stop talking ( )the teacher came in.直到老师来了,他们才停止了谈话.这两个空添啥?是用until还是用till?

问题描述:

They ( )stop talking ( )the teacher came in.直到老师来了,他们才停止了谈话.
这两个空添啥?
是用until还是用till?

第一个空didn't
第二个空为until