8, If you turn off the lights before going out, you will save electricity.
9, If we let cars stay at home, the air will be fresher.
10, If we recycle the used paper, the trees will be preserved.
11, If we use bikes, we will not produce smoke.
12, If we send old clothes to the charity, people will take them away.
13, If you don’t throw cans, the streets will be clean.
14, If we plant trees, there will be more oxygen.
15, If we keep the water clean, the fish will not die.
16, If the rivers are clean, we can swim in.
17, If we take a shower, we will save water.
18, If we use energy saving lights, we will save electricity.
19, If we put rubbish bins in the school yard, students will put garbage in.
20, If we use cloth bags, we will reduce rubbish.
