I. Are the sentences correct in the use of "and" or "so that"?

1. I think students should walk to school so that we should reuse old books. ×
   Correction: "so that" is used incorrectly here. The sentence doesn't connect logically. It should be split into two separate ideas or use "and" instead of "so that."

2. We will collect plastic bottles, and they will help recycle them. ✓

3. Everyone should reuse envelopes so that we will not waste paper. ✓

4. We should use public transportation so that we can help reduce air pollution. ✓

5. We shouldn’t throw garbage into rivers and we will save the homes of water animals and plants. ×
   Correction: This sentence should use "so that" instead of "and": "We shouldn’t throw garbage into rivers so that we will save the homes of water animals and plants."

II. Complete the sentences using "and" or "so that." Add a comma where necessary.

1. We should take a bus often, ___ we can help reduce air pollution in the city.
   Answer: We should take a bus often, so that we can help reduce air pollution in the city.

2. At school we learn that we should save energy, ___ we shouldn’t waste paper.
   Answer: At school we learn that we should save energy, so we shouldn’t waste paper.

3. We should turn off air conditioners when we leave, ___ we won’t waste electricity.
   Answer: We should turn off air conditioners when we leave, so that we won’t waste electricity.

4. We should reduce our use of water, ___ we should recycle things more often.
   Answer: We should reduce our use of water, and we should recycle things more often.

5. We should clean up the beach, ___ we should plant more trees along the coast.
   Answer: We should clean up the beach, and we should plant more trees along the coast.

To reduce air pollution, we should use public transportation more often, walk or cycle instead of driving, and use energy-efficient appliances. We shouldn't burn trash or use vehicles that emit a lot of exhaust.

To reduce land pollution, we should reduce, reuse, and recycle materials, properly dispose of waste, and avoid littering. We shouldn't use non-biodegradable products excessively or dump waste in unauthorized places.

To reduce water pollution, we should avoid using harmful chemicals in households, properly dispose of hazardous materials, and clean up local water bodies. We shouldn't dump trash, chemicals, or oils into rivers and oceans.

I. Put the words in the correct order to make complete sentences.

1. water/ The/ be/ should/ clean/ people/ local/ it./ use/ that/ can/ so
   Answer: The water should be clean so that local people can use it