He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.
—When did he leave the classroom? —He left _____you turned back to write on the blackboard.
____he thought he was helping us with the work, he was actually in the way.
Hearing his words ,I couldn’t decide _____or remain .
Questions and exercises are given by the computer, which decides ______ to move the students ahead, review an easier level, ____ give more work on the same level.
—Will you go to Mary’s birthday party? —No, ____ invited, I can’t go to it. I’ll be too busy then.