It is 1965，a 1ittle boy is on the beach (海滩) with his parents. He is four years old. The boy plays near the water. He walks into the water. His parents aren’t watching him．
The water is over the boy’s head! A woman sees the boy. She picks up the boy and carries him to his parents. The woman’s name is Mrs Blaise．
It is 1975,ten years 1ater.The boy is on the same beach. He is 14 years old now. He is big and strong. He is a good swimmer. A man is in the water. The man can’t swim. ‘Help! Help!’ the man cries．
The boy runs into the water. He swims to the man and pulls the man to the beach. ‘Thank you. Thank you.’ says the man. Who is the man? His name is Mr Blaise. He is Mrs Blaise’s husband．
经过椭圆
的一个焦点和一个顶点，则该椭圆的离心率为