下列说法正确的是（    ）

骑自行车时用力蹬踏使力加速的能量是____。

Lily's family

    Lily is an American girl . She lives in Beijing with her parents and her brother.

    Lily and her brother are students. They study in the same school. Lily is twelve years old. She likes making kites and playing the piano. Lily's brother is 10 years old. He likes playing football. They often goes hiking on the weekends.

    Lily's father is tall and strong. He is a teacher. He teaches math in a high school. He often goes to work by bike. When it rains ,he drives to work. Lily's mother is very beautiful. She is a writer. She writes the TV show for the actors. She always stays at home because she only needs to write the TV show on the computer. Lily's grandparents are farmers. They live in a small village in America.They have a small farm. And they plant potatoes and many other vegetables on their farm.

    Yesterday Lily's grandparents came to Beijing by plane. Lily and her brother met them at the airport. Then Lily and her grandparents climbed the Great Wall ,visited the Summer Palace and the Palace Museum together. They all enjoyed themselves.

根据短文内容判断正误。