Nowadays, pets become so close and friendly to our human-beings that more and more people enjoy keeping them. Pets can bring them a lot of joys and happiness, because playing with pets is a good way to communicate with the nature. Besides, pets can comfort old people who live alone. With the companion of pets, they won’t feel lonely. Nevertheless, I’m not interested in keeping pets at all. For one thing, keeping pets is bad for environmental protection, since pets usually make a lot of noise and contaminate the roads. For another, the virus carried by pets may cause fatal disease. What’s more, sometimes pets may attack people when they are unhappy. Consequently, we had better not keep too many pets, so as to ensure our health and security. Besides, those pet lovers must take some effective measures to prevent their pets from hurting people and polluting our environment.