It was a moving moment at the National Zoo in Washington. Thousands people came to say goodbye to the zoo's most popular star, is actually a panda. Bao Bao, the panda's name, left for her new home back in Chengdu, China on Feb. 22, 2017. She's the first female panda born in the US and (win) the hearts of many Americans since her birth three and a half years ago. Bao Bao must be sent back to her (origin) hometown due to an agreement between China and the US that demands every baby panda should return to China by the age of four. Pandas' lovely black-and-white appearance (make) them popular around the world. In fact, in the past they were sent to other countries as gifts, known as "Panda Diplomacy (外交)". Now, pandas face the problem of (die) out and we can (rare) see them in the wilderness. Therefore, China has stopped giving away pandas for free because of (it) decreasing number. Oncontrary, any zoos outside China wanting a panda must offer a fee (protect) this kind of precious animal.
