~ ( Chúc bạn học tốt ^^ ) ~

I)

1) learned

2) don't have

3) attend

4) will die

5) doesn't have

6) was not 

7) will be clean

8) wasn't

II)

1) I told a joke, but nobody laughed.

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

3) The city suffers from air pollution and water pollution.

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

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

=>
I/
1. learned
2. don't have
3. attend
4. will die
5. doesn't have
6. were not
7. will be clean
8. were not
II/
1. I told a joke, but nobody laughed.
2. You must study harder, or you will go into another class.
3. The city suffers from air pollution and water pollution.
4. I knew her family, so I did what I could for her.
5. We can't afford energy-saving light bulbs because the light bulbs are too expensive.