=>
15. Renewable energy will be used in the future.
16. That school is hers.
17. How long did it take you to fly from Hongkong to Hanoi?
18. My mother is a good cook.
19. I am not interested in roller-skating.
20. Why didn't you come/go to class last Monday?
21. I didn't have a tootache and they didn't, either.
22. I spend about two hours each day doing my homework.
23. Will you take care of the house while I am away?

`Azzuri#`

15.They will use renewable energy in the future.

`->`Renewable energy will be used in the future.
16.That is her school.

`->`That school is hers.
17.How long was your flight from Hongkong to Hanoi?

`->`How long did it take you to fly from Hongkong to Hanoi?
18.My mother can cook very well.

`->`My mother is a good cook.
19.Roller-skating doesn't interest me.

`->`I am not interested in roller-skating.
20.Why were you absent from class last monday?

`->`Why didn't you go to class last Monday?
21.I didn't have a toothache and They didn't have a toothache.

`->`I didn't have a toothache and they didn't, either.
22.It takes me about two hours

`->`I spend about two hours each day doing my homework.
23.Will you please look after the house while I am away?

`->`Will you take care of the house while I am away?