15. It's been ten years since we last saw our friends, who are coming to visit us this weekend.
Rewrites using the prompts:
1. If you don't ride your bike carefully, you may have an accident.
2. If I did my homework, my teacher wouldn't always get angry with me.
3. If you attend the class regularly, you can pass the test easily.
4. If you leave home now, you will miss the flight.
5. If I were good at cooking, I could become a chef.
6. If you don't ride your bike carefully, you may have an accident.
7. If she had friends, she wouldn't feel lonely.
8. If Katie didn't work too much, she wouldn't usually be tired.
9. If this boy didn't eat too many snacks, he wouldn't be so fat.
10. If we had time, we could attend English class.
11. If he didn't have a weak heart, he would watch horror films.
12. If you spent more time reading English books, you would improve your English.
13. If Mai didn't often talk to foreigners, she wouldn't be fluent in English.
14. If I knew German, I could reply to his email.