题目

Whatever your reasons are for buying a used TV, there are a few things that you should keep in mind. Why is the used TV put up for sale? Does the owner put it up for sale because it broke down? Does he sell it because the picture is not good enough? Or does he do that just because he got bored of it and bought a new one for himself? These are questions that must be answered before you consider buying a used TV. If the owner is selling it because he found a defect (瑕疵) with the TV, even if the defect was mended, you should stay away from such television sets. The price of a secon伽利略认为，速度变化均匀的运动是一种最简单的变速运动，伽利略清楚地分析到，在一段速度均匀变化的运动中，中间时刻（运动了一半时间）的速度和中间位置（运动了一半位移）的速度是不同的．对于匀变速直线运动来说，中间时刻的速度和中间位置的速度，究竟哪个大？下列判断中正确的是A.匀加速直线运动中，中间时刻的速度比中间位置的速度大B.匀减速直线运动中，中间时刻的速度比中间位置的速度大C.匀加速直线运动中，中间位置的速度与中间时刻的速度一样大D.匀减速直线运动中，中间位置的速度比中间时刻的速度大