Fill the blanks

13. They used to (walk)
14. Mrs. Thanh should (do)
15. Most of people (install)
16. We (save)
17. We shouldn't (eat)
18. Nam is a hard-working
19. She (water)
20. He (buy).
папу
to work last year.
mations. It (De) a very busy week.
_more exercises and (drink)
more water.
solar energy on the roof of the house in the future.
a lot of trees if we use less paper.
much fast food. We should (eat).
student. He (pass).
the flowers in the garden now.
healthy food.
the exam easily this year.
a new bike for her daughter next week.