Dưới đây là các câu đã được viết lại dựa vào từ gợi ý:

1. **It takes thirty minutes to water these flowers in the garden.**
- **Watering these flowers in the garden takes thirty minutes.**

2. **Although my mother cooks very well, I can't cook. (however)**
- **My mother cooks very well; however, I can't cook.**

3. **My father allows me to buy this gift for my sister. (let)**
- **My father lets me buy this gift for my sister.**

4. **It's raining; however, the farmers still work in the paddy field. (Although)**
- **Although it's raining, the farmers still work in the paddy field.**

5. **Travelling by air is more interesting than travelling by car. (She prefers)**
- **She prefers travelling by air to travelling by car.**

6. **It takes a day to finish this task.**
- **Finishing this task takes a day.**