问题 选择题
电气化铁路的输电线常用图所示的方式悬挂在钢缆上.钢缆的A端固定在电杆上,B端连接在滑轮组上.滑轮组由a、b、c三个滑轮构成,配重P由多个混凝土圆盘悬挂在一起组成,配重的总重为G,若不计摩擦和滑轮的重量,则以下说法中正确的是(  )

A.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

B.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

C.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

D.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

答案

答案:A

阅读理解

No matter where he lives, 16-year-old Danny Lopez feels like an outsider: he is half-Mexican and half-white.

At his private high school in wealthy northern San Diego, California, US, Lopez is too brown to fit in, whereas for the Mexican side of his family in National City, just a dozen miles from the border, he is too white to belong.

Different from both sides, Lopez is silent in school. He focuses on his passion for baseball and working hard to improve the pitches (球场) that have kept him off the school team.

Mexican Whiteboy, by Matt de la Pena, is about a teenager’s search for identity. It was named as one of the Top Ten Best Books for Young Adults in 2009 by the US Young Adult Library Services Association.

When Lopez’s mother decides to go to live with her wealthy white boyfriend in San Francisco, he chooses to spend the summer with his father’s family in San Diego. It’s a trip to explore roots and self-identity, filled with unexpected friendship.

There he meets Uno, of mixed heritage (遗传) like himself, also with a divorced mom. Uno understands Danny’s split background and helps him improve his baseball skills. Both boys have big league dreams, but they both have to learn to come to terms with their mixed heritages before they can achieve their goals.

Aside from discussions of racism, Mexican Whiteboy takes on other issues, such as the importance of family and the negative influence of hiding the truth. It also shows how sports can draw cultures together.

小题1:The reason why Lopez feels like an outsider lies in the fact that ___________.

A.he is a Mexican

B.he lives in San Diego

C.he is half-white and half-Mexican

D.he studies in a private school小题2:Most probably “Mexican Whiteboy” is a ____________.

A.book

B.club

C.newspaper

D.organization小题3:When Lopez found it is hard for him to fit in, he ____________.

A.starts writing a book about himself

B.begins to look for identity with the help of Mexican Whiteboy

C.loses his interest in baseball

D.works in the fields in which he was kept off the school team小题4:Lopez and Uno have a lot in common except that ____________.

A.they both have a divorced mom

B.they both have mixed heritage

C.they were both in the school baseball team

D.both of them have big league dreams

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