12 Resistant to household chemicals and swimming pool salts --- Not less than UB level Class UA Eligible 13 Internal exposure index IRa --- ClassA Decoration Materials:IRa≤1.0 0.6 ClassA ClassB Decoration Materials:IRa≤1.3 External exposure index Ir --- ClassA Decoration...
关于速度的描述,下列说法正确的是 ( ) 根据您输入的内容,为您匹配到题目: **关于速度的描述,下列说法正确的是 ( )** A. 电动自行车限速20 km/h,指的是平均速度大小 B. 子弹射出枪口时的速度大小为500 m/s,指的是平均速度...