Ответ:

1. Nature would be cleaner if people littered less.

2. If I had prepared better, I would have gotten an A.

3. The soup would taste better if I added more salt.

4. I would read books if the holidays started.

5. I would help you if I could.

6. I'd be freezing if I didn't wear a jacket.

7. If I had a dog I would play with him all day.

8. If I could I would draw you.

9. I'd eat if I was hungry.

10. I can't imagine what if we didn't have the internet.

надеюсь я правильно понял вопрос. как-то так.