Перепишите каждое предложение дважды: в 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.
Просто заменю в 1
Is на was , must на had to
Is на will be, must на will have to
Во 2
Is на was , must на had to
Is на will be , must на will have to
3
Must на had to
Must на will have to
4
Can't на couldn't , is на was
Can't на won't be able to , is на will be
Удачи)