Paraphrase the sentences and use possessive pronouns.
For example:
This is his sandwich. / This sandwich is his.

1. This is her turtle. / This turtle is ... .
2. That is your bike. / That bike is ... .
3. This is his phone. / This phone is ... .
4. Those are their T-shirts. / Those T-shirts are ... .
5. These are our seats. / These seats are ... .
6. This is my watch. / This watch is ... .