There, they're, or their.

[Anna]

- They prepared [....] trip to France very well.
- [....] are only two cookies left in the box.
- After searching for a long time, they found out that [....] cat was right [....].
- A fire destroyed [....] house.
- They forgot [....] keys and the door was locked.
- It will be crowded at the festival, let's get [....] early.
- Where are the girls? [....] late as usual.
- [....] clothes were soaked after walking in the rain.
- When should I visit my cousins? [....] never home.
- The house is haunted. I don't want to stay [....].

[NagNag]

- [......] saw a dirty restroom and [......] didn't want to go [......].
- [......] shoes were so muddy after walking in the rain.
- Do you think [......] is room for all of us?
- [......] fastened [......] seatbelts because it was safer.

[username1224]

- [They] saw a dirty restroom and [they] didn't want to go [there].
- [Their] shoes were so muddy after walking in the rain.
- Do you think [there] is room for all of us?
- [They] fastened [their] seatbelts because it was safer.