—Is Jack on duty today? —It_____ be him. It’s his turn tomorrow.
The field research will take Joan and Paul about five months;it will be a long time_____we meet them again.
My parents live in a small village. They always keep candles in the house ___ there is a power cut.
It is difficult for us to learn a lesson in life _____we’ve actually had that lesson.
____fire, all exits must be kept clear.
—Where’s that report? —I brought it to you ____you were in Mr. Black’s office yesterday.