题干

关于浮力,下列说法正确的是(  )

A:在水中会下沉的金属块不受到浮力

B:浮力的大小与物体浸没的深度有关

C:浮力的大小与物体的形状有关

D:浮力是由于物体上、下表面受到的压强不同产生的

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答案(点此获取答案解析)

D

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阅读理解

    Guide Dogs of America, A History is the book that we all have been waiting for. It's a book that tells how and where the guide dog movement really started, with information never before revealed--until now. After reading this 200-page, picture-filled work, you will know about every aspect of Guide Dogs of America(GDA) from its inception to how it has become one of the top guide dog schools in the country.

    Joseph W. Jones, Sr., was refused a guide dog because of his age--he was fifty seven--but he would not accept defeat. He researched the guide dog movement and with the help of the International Association of Machinists and Aerospace Workers, established his own school, one that would provide guide dogs free of charge to visually impaired people regardless of their age.

    The school graduated 18 guide dog teams the first year with students staying at, GDA's first trainer, Lambert Kreimer's house on South Virginia Avenue in Burbank, and Jones manning the office on Lankershim Boulevard in North Hollywood.

    In 1952, Jones addressed the quadrennial(四周年纪念的) IAM Grand Lodge Convention in Kansas City, Missouri. “I sincerely prayed to God for two things,” Jones said. “After my wife passed away and left me with a ten-year-old boy, I prayed that I would be spared long enough to see this organization well established and that my ten-year-old boy would become a man. Both prayers have been answered. The organization is well established, it is in the hands of the IAM and my boy is a man, and I am proud to say that today he is a member of the IAM.”

    Jones' pray for a successful organization had been answered now, ten years after he was rejected for being too old, his dream of having a guide dog for himself, hundreds of others had already been given the gift of sight because of his drive and determination. That school, now known as Guide Dogs of America, has provided guide dogs to thousands of people free of charge.