my brother has just bought a car . ____ quite old, but he's very proud of it . he boasts all the time to his friends about speed and comfort ​

It's quite old, but he's very proud of it.

it's (it is)

Yes, you're right. It's is the contraction of it is, while its is the possessive form. So the correct sentence is:

My brother has just bought a car. It's quite old, but he's very proud of it. He boasts all the time to his friends about speed and comfort.

1. First, congratulations to your brother on his new car purchase!

2. Despite being quite old, it seems your brother is still very proud of it.
3. He boasts to his friends about both its speed and comfort, which shows his enthusiasm for the car's features.
4. It's great that he is excited to share his new acquisition with his friends.
5. Older cars can still offer decent speed and comfort, so it's a testament to your brother's ability to find the right car for his needs.