听力原文：Woman: Mr. Bacon, what is your job exactly? Bacon: I'm a vet, looking after sheep, horses, dogs, cats. We even have lions and tigers at the zoo. Woman: What sort of pets do people bring to your clinic? Bacon: Mostly dogs and cats but then we have snakes and parrots and all other animals people keep as pets. Woman: Snakes? Why do you think people keep snakes? Bacon: I quite like snakes, but I wouldn't want one as a pet, urn... (1[A]) some people are very keen on them. Woman: Maybe they keep snakes to frighten others. All right, do you think people spend more money on their animals than their children? Bacon: It depends on the people. Some are very good with their animals, some treat them far better than they would their kids, and unfortunately some are cruel with the animals. Woman: (3[C]) What experience have you had of people who treat their animals too well? Bacon: Lots of animals come here with lipstick marks on the head. We regard that as a specific sort of condition here. Woman: Are animals good for people's health? Bacon: Well, (2[B]) they seem to help old people, These people see one person every two days, but their animal is with them all day, and it's a companion. Woman: Above all, why are you interested in your job? Bacon: Maybe the animals sometimes attack me and there is much paper work. (4[D]) The thing i like best is to deliver new animals. It always amazes me one moment you have one mother and the next moment you can have a pile of animals. According to Mr. Bacon, people keep snakes because ______.