Here are the rephrased sentences based on the prompts provided:

1. I’d prefer it if you didn’t smoke in here.
→ **You mind smoking in here?**

2. “I cannot go to the science class tomorrow,” said Hoa.
→ **Hoa said that she couldn't go to the science class tomorrow.**

3. This is such a difficult test that all the candidates can’t finish it on time.
→ **The test is too difficult for all the candidates to finish on time.**

4. People use too much fertilizer, so the land will be spoiled.
→ **Land will be spoiled if people use too much fertilizer.**

5. My parents want me to learn something interesting.
→ **My parents insist that I learn something interesting.**

Feel free to ask if you need further assistance!