DrPeter Spence，________ headmaster of the school，told us，“________fifth of pupils here go on to study at Oxford and Cambridge”

Teachers should bear in mind that each student’s improvement ______.

Mr. Wang, must I come again to clean the classroom on Sunday—No, you____ . I have asked Kate to do it.

You must be very tired. Why not ________ a rest

I tried phoning her office, but I couldn’t ____.