Read the text and answer questions 4-5.Dogs are one of the most common domestic animals. Many people have them as their pets. It is because they are friendly and loyal. There are also many different kinds of dogs. They hav different sizes and personalities. We often see many dogs diggin in their owner's yards. Digging is actually a common behaviour for dogs. It is because of their natural instinct. Dogs usually dig a hole to hide their food in the dirt. They even hide their bones there. Sometimes, they also dig a bigger hole in a colder area shelter.

4. Why do humans keep dogs as their pets?

5. What do they usually do in the holes they dig?​