20) She stayed in bed because of her sickness.

---> Because

21) You didn"t work hard. You got bad marks.

---> If

22) The boy can"t wear the shirt because it"s very tight.

---> The shirt is so

---> The shirt is too

23) Both Peter and Mary enjoy scientific expeditions.

---> Mary enjoys scientific expeditions, and so

---> Peter enjoys scientific expeditions, and Mary

24) Mike is a more careful driver than his brother.

---> Mike drives

25) She worked hard so she got high wages.

---> If

26) Unless you phone me tonight, you won"t get any

information.

---> If

27) Tom cried a lot when he was a child.

---> Tom used to

28) This problem is very difficult. He can"t solve it.

---> The problem is too

---> It is such

The problem is so

20, Because she was sick, she stayed in bed

21, If you had worked hard, you wouldn't have got bad marks

22, -The shirt is so tight that they boy can't wear it

-The shirt is too tight for the boy to wear

23, -does Peter

-enjoys scientific too

24, Mike drives more carefully than his brother

25, If she hadn't worked hard, she wouldn't have got wages

26, If you don't phone me tonight, you won't get any information

27, Tom used to cry a lot when he was a child

28, -This problem is too difficult fo him to solve

-It is such a difficult problem that he can't solve it

-This problem is so difficult that he can't solve it