If you don't have a rest, you really will be ill

17) If you don't have a rest, you really will be ill.
-> Unless
18) The water was so cold that the children could not swim in it.
-> The water was not
19) Ba was arrested bt the police.
-> The police
20) There are a number of people waiting to see you.
-> A number of people
21) I hope to see you at Christmas.
-> I am
22) Your hair is too long. You'd better have cut it.
-> Your hair
23) Are you against working on Sunday?
-> Do you object
24) I have to writes 6 letters a day.
-> There are
25) People always laugh at his funny face, he doesn't like it.
-> He dis likes
26) You are not permitted so smoke in the hall.
-> Smoking
27) I wish I had gone on holidaywith my friend.
-> I regret
28) Tom's father no longer smokes eigarettes.
-> No
29) This baby rarely cries during the night.
-> Rarely
30) People did not discover Aids until 1981.
-> Not until