【单选题】有包装或放置在一般容器内的物品,其活性指数为( )。
【单选题】气固催化反应的内扩散模数 ,其中L为特征长度,若颗粒为球形则L=( )。
【单选题】All I suggest is that we ________electric wires out of the reach of children.
【简答题】In an electric lamp there should not be any oxygen in which the wires may burn away.
【单选题】气固催化反应的内扩散模数 ,其中L为特征长度,若颗粒为圆柱形则L=()。
【单选题】Electric wires in your house are ___________ with poor conductors like rubber or silk.
【单选题】气固催化反应的内扩散模数 ,其中L为特征长度,若颗粒为平片形则L=()。
【多选题】读下列投影图,能直接读出AB直线实长或通过作图读出AB直线的实长投影图的是( )。
【判断题】Electricity comes into our houses by flowing through electric wires and cables in the sky.