— What are those? —. A.Those are books. 发布时间:2017-06-23 21:15 │ 来源:www.tikuol.com 题型:选择题 问题: — What are those?— .A. Those are books. B. They are books. C. It’s a book.
题型:选择题 在“验证机械能守恒定律”的实验中,打点计时器接在电压为E,频率为f的交流电源上,在实验中打下一条理想纸带,如图所示,选取纸带上打出的连续5个点A、B、C、D、E,测出A点距起始点的距离为S0,点AC间的距离为S1,点CE间的距离为S2,已各重锤的质量为m,当地的重力加速度为g,则从起始点O到打下C点的过程中,重锤重力势能的减少量为△EP= ,重锤动能的增加量为△EK= 。 查看答案
题型:选择题 They are always singing songs to ________ their spirits when they meet with trouble.[ ]A. keep off B. keep backC. keep up D. keep on 查看答案