The man kept silent in the room unless_______.
_______every member has arrived, let’s set about _____ the plan for the next five years.
It is surprising that such a young boy can swim ______ the river ______ 100 meters wide.
_____ in a heavy snow, he didn’t get there in time.
The criminals ______ in a hotel the other day were connected with a murder(谋杀).
With a lot of things , John will have a difficult time.