6．21．What was the main reason for people to have dogs in the past？ A．To make friends B．To keep them safe． C．To help them work． 22．What is a dog for a child？ A．A playing partner． B．A helpful brother． C．A smart teacher． 23．What do young people think of dogs now？ A．Dogs help them with everything． B．Dogs are their children． C．They regard dogs as their friends． 24．Why do old people keep dogs？ A．Dogs make them feel safer． B．They regard dogs as their children． C．Dogs can play with them． 25．Which of the following is true？ A．The dog is one of the most useful animals． B．More and more people keep dogs for their safety． C．Now many people don't like dogs．
