Here are the corrections for each sentence:

1. **Mistake:** "love"
**Correction:** "loves"
**Corrected Sentence:** "My sister loves going to the cinema very much."

2. **Mistake:** "walk"
**Correction:** "walks"
**Corrected Sentence:** "My best friend walks to school every day."

3. **Mistake:** "doesn’t" (should match the subjects)
**Correction:** "don’t"
**Corrected Sentence:** "Lan and her sister don’t like cooking very much."

4. **Mistake:** "Do he"
**Correction:** "Does he"
**Corrected Sentence:** "Does he go cycling with his father at weekends?"

5. **Mistake:** "watered"
**Correction:** "water"
**Corrected Sentence:** "We didn’t water the flowers, so they died."