Sure, here are the sentences rewritten in the 3rd person singular:
They often visit their granny.
- He/She often visits his/her granny.
We live in Leeds.
You usually speak too quickly.
- He/She usually speaks too quickly.
Do you like boiled potatoes?
- Does he/she like boiled potatoes?
Good animals always obey their masters.
- A good animal always obeys its master.
The boys box in the gymnasium on Fridays.
- The boy boxes in the gymnasium on Fridays.
His dogs always attack the neighbors.
- His dog always attacks the neighbors.
Heavy trucks make a lot of noise.
- A heavy truck makes a lot of noise.
These transformations involve several changes:
- For most verbs, add an "s" or "es" at the end of the verb in the 3rd person singular form.
- Adjust pronouns and subjects to align with the singular form.
- Ensure that the sentence structure remains grammatically correct after the changes.