As you know, some people like to keep pets at home while some people do not like them at all as they think animals make a loud noise and are dirty. In fact, some pets can be useful to the owners as well, for example, dogs and cats. Even though there are many types of pets, the most common pets are dogs and cats and these two types of pet are useful because dogs help us drive away burglars while cats scare away rats which are dirty and can be discase-carriers. Obviously. pets can be good companions for human beings as well.