Перепишите каждое предложение дважды: в прошедшем и будущем времени.
1. It is quite clear to everybody in the family that he must start getting ready for his exam instead of wasting time.
2. It is impossible to do anything in such a short time. I must ask the chief to pit up my report.
3. You must listen to the tape recording of this text several times.
4. He can`t join the party because he is busy.