阅读理解
A
    My name's Li Yan．I'm from Belling and I'm 13 years old.I study in No．1 Middle School．I'm in Class 2．Grade 7．I'm in the school music club．I can play the guitar well and I am good at playing the piano．Lang Lang is my favorite musician．I dream of being a musician like him．
    LiYue is my sister．We are twins(双胞胎)．We go to the same school， but she is in Class 4．Grade 7．She can play ping-pong very well and she is in the sports club．She likes Zhang Jike and Ma Long best．She often watches them play ping-pong on TV.
    My sister and I are learning how to swim．We are not good at it now,but we are trying our best(尽我们最大的努力)to learn it．It is a really healthy sport．
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直线的倾斜角是（       ）

依次填入下列横线的词语，最恰当的一组是（   ）
①、与其说这雄伟的建筑群是人类的奇迹，         说它们是历史发展造就的产物。
②、中华人民共和国的每位公民都有        老人的义务。
③、演员们曾阅读大量资料，潜心观察人物并刻意模仿，        最后的表演让人信以为真。

行人在横过道路时，应注意观察道路上通行的车辆。您认为在横过道路时，错误的行为是（    ）。

一个圆柱的高扩大2倍，底面积缩小2倍，它的体积不变。