1. You never check your writing, so you make a lot of mistakes

If you checked your writing, you wouldn't make a lot of mistakes.

2. I never do my homework, so my teacher always gets angry with me

If I did my homework, my teacher wouldn't get angry with me.

3. She doesn't have any friend, so she feels lonely

If she had (some) friends, she wouldn't feel lonely.

4. Katie is usually tired because she works too much

If Katie didn't work so much, she wouldn't usually be tired.

5. This boy eats too many snacks. That's why he is so fat

If this boy didn't eat too many snacks, he wouldn't be so fat.

6. We can't attend English class because we don't have time

If we had time, we could attend English class.

7. He doesn't watch horror films because he has weak hearts

If he didn't have weak hearts, he could watch horror films.

8. I think you should spend more time reading English books

If I were you, I would spend more time reading English books.

9. Mai often talks to foreigners. That's why she fluent in English

If Mai didn't often talk to foreigners, she couldn't be fluent in English.

10. I can't reply to his email because I don't know German

If I knew German, I could reply to his email.