越快越好!Many people like dolphins.They are very _____ to people

Many people like dolphins.They are very kind to people.They swim fast and jump very high.They can play with a ball.They can stand up and walk on water!If you fall into the water and can't swim,they may come up and rescue you.
Dolphins are whale-like mammals that live in water.The blow-holes in the top of their heads help the dolphins breathe.
Dolphins are still alive.How interesting!The mother dolphin is called a cow,and the baby dolphin is called a calf.
Dolphins can see,hear and taste,but do you believe that they can not smell things?Dolphins swim in groups called school.If a dolphin is ill,they will help it.
People like to watch dolphins swim and play games.They can jump in the air.Some scientists believe dolphins can talk to each other.Maybe some day we will learn to talk to dolphins.