8. conserve

9. replacing 

---//---

I told a joke but nobody laughed.

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

The city suffers from air pollution and the city suffers from water pollution.

I knew her family so I did what I could for her.

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

---//---

If he learned to drive...

...if they don't have a map

If the students attend QT school...

---//---

1. after

2. on

3. for

4. off

5. on

6. away

7. out

8. up

9. up

10. off

---//---

1. effective

2. pollution

3. energy

4. electricity

5. nuclear

6. heat

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