. Many wildlife habitats will be destroyed if man _ (keep) polluting the environment.2. If we dump all sorts of chemicals into rivers, we _ (not be able to) swim in them in the future.3. If we _ (not stop) cutting down so many trees, we _ (endanger) our oxygen supply.4. If the global temperature _ (rise), sea levels _ (rise) too.5. People _ (run out of) drinking water one day if they _(not use) it more rationally.6. If a human _ (want) to help the planet, then he _ (have to) change his habits.

Many wildlife habitats will be destroyed if man keeps polluting the environment.
2. If we dump all sorts of chemicals into rivers, we will not be able to swim in them in the future.
3. If we do not stop cutting down so many trees, we will endanger our oxygen supply.
4. Soon the Earth’s resources will be exhausted if the human population continues to grow.
5. If everybody continues to use aerosols and CFCs, the hole in the ozone layer will get bigger.
6. If the sun radiation can’t escape into space, Earth’s temperature will increase steadily.
7. If the global temperature rises, sea levels will rise too.
8. We’ll threaten our own existence if we do not cut down on waste rapidly.
9. People will run out of drinking water one day if they do not use it more rationally.
10. If he wants to help the planet, then he has to change his habits