IV,

1, learnt

2, don't have

3, attend 

4, will die

5, doesn't have

6, wasn't

7, will be clean

8, wasn't

V,

1, after

2, on 

3, for

4, off

II,

1, happily

2, economical

3, products

4, readers

5, necessities

6, appliances

7, innovations

8, conserve

9, replacing

10, solar

III,

1, I told a joke but nobody laughed.

2, You must study harder or you will go to another class.

3, The city suffers from air pollution and he city suffers from water pollution.

4, I knew her family so i did what i could for her.

Xin ctlhn nhe <33

IV.

1. learnt

2. don't have 

3. attend

4. will die

5. doesn't have

6. weren't

7. will be clean

8. weren't

V.

1. After

2. On

3. For

4. Off

II.

1. happily

2. Economist

3. Product

4. Reader

5. Neccesary

6. Appliance

7. Innovation

8. Conserve

9. Replacement

10. Sun

III.

1. I told a joke but nobody laughed

2. You must study hander or you will go into another class

3. The city suffers from air and water pollution

4. I know her family so I did what I could for her

5. We can't afford energy- saving light bulbs, because they are too expensive