A: Do you have a pet?

B: Yes, I do. I have a cat. I like it very much.

A: Why?

B: Because it can help us catch a mouse.

A: What color is it?

B: It's black and white. And it has two big eyes. How about you? What pet do you have?

A: I don't have a pet.

B: Do you want one?

A: Yes, I do. I want a dog.

B: Why?

A: Because dogs are very smart. And all of them are people's good friends. They can do many thing for people.

B: So why not buy a dog now? There is a pets shop just in front of you.

A: That sounds nice. Let's go.