阅读短文，判断正误。
Mr Smith and Mrs Smith live in a big city. There is a park near their home and in the park there is a lake. They have a little daughter. Her name is Lucy. She is four years old.
Mr Smith has a dog. The dog is big and strong. He likes it very much. He walks the dog in the park. But Mrs Smith doesn't like the dog. She thinks the dog is very dirty(脏的).
One day Mr Smith walked the dog with his family in the park. While the adults were talking, Lucy walked to the lake. It was very dangerous(危险的). The dog followed her. Lucy fell into the lake when she was trying to pick a flower. The dog barked(狗叫) and jumped into the lake right now.
When Mr and Mrs Smith heard the dog barking, they ran to the lake. They saw the dog swimming to the bank. It was carrying little Lucy. Oh! The dog saved the little girl. It was so clever and brave(勇敢的). From then on, the whole family like the dog.