1. If light pollution happens, animals will change their behavior patterns. Câu đk loại 1 diễn tả sự việc có khả năng xảy ra / sự thật hiển nhiên.

2. Because of too much light pollution , so we can't see the starts at night.

3. Ships spill in oceans and rivers leads to many aquatic animals and plants die. - Vế đầu là nguyên nhân, vế sau là kết quả, leads to là vì thế → thêm leads to vào giữa nguyên nhân và kết quả.

4. If I were a environmentalist, I would tell everyone to save natural resources so that we will have a fresh and clean Earth to live. Câu đk loại 2 diễn tả sự việc đã / mong ước xảy ra trong quá khứ.

1. If light pollution happens, the animal will change their behavior patterns.
2. Because there is too much light pollution, we can't see the stars at night.
3. Ships spill in oceans and rivers lead to the death of many aquatic animals and plants.
4. If I were an environmentalist, I would create a project with plastic.