their / they're / there?

__ is a dog playing in the garden.
1. their
2. they're
3. there
__ car has broken down.
1. their
2. there
3. they're
Where are the children? __ at home.
1. their
2. there
3. they're
Jane and Tom are waiting for __ mother.
1. their
2. there
3. they
Have you seen my glasses? Yes, you've left them over __
1. their
2. there
3. they
__ are many students in front of the school.
1. their
2. there
3. they
What are __ doing?
1. their
2. there
3. they
__ having a shower.
1. their
2. there
3. they're
Look! __ train is leaving!
1. their
2. there
3. they're
Where are the plates? Oh, __ they are!
1. their
2. there
3. they