阅读下面短文，用括号内所给动词的适当形式填空 (必要时可加情态动词或助动词)。
    Many of us Chinese are Yao Ming's fans. Of course we all know he____( retire ) for several months . Yao made farewell(告别) conference Wednesday. He said he  ____(force )to make this decision by a series of foot and leg injuries. Yao played eight seasons in the NBA.
“Today is an important day for me and ____ (hold) a special meaning for both my basketball career and my future,”Yao said. “ I____(think) about my future for a long time. Today I am announcing a personal decision, ____ (end ) my career as a basketball player and officially retire. But one door is closing and another one____ (open).’’
    Yao said he____ ( return) to work with his former Chinese team, the Shanghai Sharks, with the possibility of____  (become) general manager. He already ____ (own) the club and wants to contribute more. He thanked a lot of people — his family, former coaches, even players like Shaquille O’Neal — “for making me a better player."
    Rockets(火箭队) general manager Daryl Morey was among those attending the farewell conference Wednesday. “I would be sorry if I wasn't here."“It's a big moment," Morey added. “Yao had a sense of humor, a great attitude and sense of responsibility. I hope we ____(continue) his culture in the NBA."

Helen is my friend. She is thirteen years old. She is ____ (study) in London, the capital city of England. She'd like to visit different ____ (place) and meet different ____ (people) when she is on holiday. She likes reading very much. Now, she's standing ____ (介词) line in a bookshop. She's buying ____ (冠词) English storybook.

史学家钱穆在《理学与艺术》一书中说过：“论中国古今社会之变，最要在宋代。……故就宋代而言之，政治经济、社会人生，较之前代莫不有变。”下列史实不能佐证这一观点的是