1£®So far Peter hasn't called(not call) back. Shall we make a phone call to him again?

2£®The boss stayed (stay) in New York for four days last week. Now he is working in China.

3£®It is the third time that you have come(come) to our school.

4£®Henry feels rather tired because he has been working (work) in the field for six hours.

5£®She ought to stop working£»she has a headache because she has been reading (read) all day long.

6£®Jones cares about you very much and has been asking (ask) about your health.

7£®Here he is! We have been waiting (wait) anxiously for him since last night.

8£®Up to now, the gifted child has won(win)three national prizes in music.

9£®I have been looking(look) for my lost book for three days£¬but I still haven't found it.

10£®The telephone has been ringing (ring) for minutes, but no one has answered (answer) it.