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某学校科技小组对一辆自制小遥控车的性能进行研究,他们让小车在水平地面上由静止开始运动,并将小车运动的全过程记录下来,通过数据处理得到如图所示的v﹣t图象,已知小车在0﹣2s内做匀加速直线运动,2﹣10s内小车牵引力的功率保持不变,在10s末停止遥控,关闭电动机.小车的质量m=1kg,整个过程中小车受到的阻力保持不变.求:
阅读下列材料材料一:人固有一死,或重于泰山,或轻于鸿毛。 ——司马迁材料二:“究天人之际,通古今之变,成一家之言”。请回答:(1)材料一是谁说的?他写的史学著作是什么?(2)材料二是这部著作编写的目的,“古”“今”分别指何时?“成一家之言”指的又是什么?
下列各项中,没有错别字的一句是( )
A. Red is my favourite colour.
B. What time does the party begin?
C. That sounds interesting.
D. It's on 5th January.
E. Can you come to my birthday party, Linda?
Peter: ____
Linda: Sure. When's your birthday?
Linda: ____
Peter: It begins at half past six in the evening.
Linda: OK.
Peter: Please bring some red things to the party. It's a "red party". ____Linda: A “red party”? ____ I can't wait.