Dưới đây là các câu đã chuyển đổi theo yêu cầu của bạn:

1. **"wish i could have finished my biology project on time (able)"**
- → **I regret not being able to finish my biology project on time.**

2. **"if only i had warned them in time (regret)"**
- → **I really regret not warning them in time.**

3. **"i regret taking up smoking (wish)"**
- → **I wish I had not taken up smoking.**

4. **"angela regrets not seeing that film (wishes)"**
- → **Angela wishes she had seen that film.**

5. **"i regret that i gave him the money (lent)"**
- → **If only I hadn't lent him the money.**

6. **"i regret not getting married (wish)"**
- → **I wish I had gotten married.**

7. **"he really regretted having taken the car out of the garage"**
- → **He wished he hadn't taken the car out of the garage.**

8. **"i regret not inviting cathy to the party (only)"**
- → **If only I had invited Cathy to the party.**

9. **"i would like the school holidays to be longer"**
- → **I wish the school holidays were longer.**

Hy vọng những chuyển đổi này sẽ giúp bạn hoàn thành bài tập của mình!