【单选题】乒乓球是我国人们最爱的运动项目之一,下列关于乒乓球受力及运动的说法中错误的是
A.
击打球的不同部位,球的旋转方向不同,表明力的作用效果与力的大小有关
B.
球在空中飞行时,如果不考虑空气阻力,则乒乓球只受重力作用
D.
运动的乒乓球在碰到桌面后会改变运动方向,表明力可以改变物体的运动状态
【单选题】在新中国的外交史上,用“小球推动大球”是指( )。
C.
用“乒乓外交”打开中日两国人民友好交往的大门
D.
用“乒乓外交”打开中美两国人民友好交往的大门
【简答题】Li Qiu is a boy of fif and studying in Grade Three at Oak school. His family lives outside the town. His parents have a farm and grow a lot of vegetables on it and they often sell them in the town...
【简答题】____是公务电话的核心,它实质上是一部由计算机软件控制的数字通信交换机,按用途可分为市话、长话和用户交换机。
【简答题】A:根据所给中文及句意,完成下列空格。(7分) The old man ____________ (刷) his dog’s fur every day. 2. Bill is very smart and he can always answer questions ______(正确地). 3. The girl is very young, but she can speak some ...
【单选题】The motorbike is out of______and hit a tree by road.
【单选题】在体育项目中称为我国的“国球”是什么球?( )
【单选题】乒乓球是我国的国球也是同学们喜爱的运动项目之一。下列说法中正确的是( )
B.
运动的乒乓球在碰到桌面后会改变运动方向,表明力可以改变物体的运动状态