13. At twelve o'clock the workers were loading the
trucks. 14. By three o'clock the workers had loaded the trucks. 15. We send our daughter to
rest in the south every year. 16. They will show this film on TV. 17. They are building a
new concert-hall in our street. 18. They have made a number of important experiments in
this laboratory. 19. Livingstone explored Central Africa in the 19th century. 20. By the
middle of autumn we had planted all the trees. 21. They will stage this play at the beginning
of next season. 22. They have forgotten the story. 23. Has anybody explained the rules of
the game to you? 24. They haven' tbrought back my skates.

13 At twelve o'clock the trucks were being loaded by the workers.

14 By three o'clock the trucks had been loaded by the workers.

15 Our daughter is sent to rest in the south every year.

16 This film will be shown on TV.

17 A new concert-hall is being built in our street.

18 A number of important experiments have been made in this laboratory.

19 Central Africa was explored by Livingstone in the 19th century.

20 By the middle of autumn all the trees had been planted.

21 This play will be staged at the beginning of next season.

22. The story has been forgotten.

23 Have you been explained the rules of the game?

24 My skates haven't been brought back.