A、Snakes. B、Ferrets. C、Spiders. D、Frogs. D原文中，女士说不知自己是否提到过其他种类的宠物：蛇、雪貂和蜘蛛。对话中没有提到青蛙，故答案为D。

M: Hello, Mary! It has been a long time since we last met.
W: Hello, Todd! Yeah, we are both very busy lately, aren’t we?
M: I’m going to ask you some questions about pets.
W: Of course, bring it on!
M: First question, do you have a pet?
W: Yes. In fact, in my mom’s house, we have three pets—two dogs and a cat. My family actually raises dogs to helping blind people.
M: Oh, really?
W: Yeah, yeah. Amazing, right?
M: Wow, how do they train the dogs?
W: How do they train the dogs? Well, I mean, it’s a long process. We get them when they’re puppies, and so we train them basic things, you know, sit, come, really basic things. Then, after they’re about two years old, they go to a different training school.
M: Oh, that’s great!
W: Yeah!
M: Well, how many dogs do they train at a time?
W: Oh, just one! You know, it is interesting, but really a tough job.
M: Oh, OK. Do you ever walk the dogs you trained, like out on the street or anything?
W: Sometimes we’ll walk them. So, yeah, you get to see them once in a while (偶尔，有时).
M: Oh, wow. That’s cool. Urn, why do people keep pets?
W: I guess the most important thing is companionship (陪伴，友谊) right?
M: That’s a good point, especially for those old people whose children are really far away and too busy to come back to visit them.
W: That’s right. They will be so lonely, and it’s not very good for health if it lasts long. But the situation may change if there is a pet around, you know, like there is always somebody there for them that will like them no matter what.
M: Yeah. Most people like dogs to be their pets, don’t they?
W: That’s right.
M: Are there any other kinds of pets that people like to raise?
W: Of course, there are. But you may feel surprised if you know what they are. I mean, my friend has a snake. I don’t know if I have mentioned that; snakes, ferrets (雪貂，白鼬) and spiders.
M: OK.
W: All kinds of things.
M: All right. There are so many. What are some costs associated with keeping a pet?
W: Food is probably the biggest cost. But also if you keep the dog, particularly a dog in your house, when it is a puppy, it will chew up (扯坏，嚼碎) everything it can, so we’re constantly replacing shoes and, you know, cleaning up pee from the carpet and things like that. So it can be a hassle (麻烦).
M: Yeah, OK. Thanks a lot for telling me so much about pets.
6. Why does the woman’s family raise dogs?
7. How does the woman’s family train the dogs?
8. According to the woman, why do people keep pets?
9. Which is NOT one of the surprising pets the woman mentions?
10. What is probably the biggest cost of keeping a pet according to the woman?