【判断题】若过滤面积为Am ,经过一段时间的过滤后,得滤液量Vm ,同时生成厚度为Lm的滤饼,滤饼空隙率为ε,固体颗粒的密度为 kg/m ,当过滤前悬浮液的浓度以Φkg固/m 清液表示,则Φ= 。
【简答题】Although they plant trees in this area every year, the tops of some hills are still ________. A) blank B) hollow C) vacant D) bare
【单选题】在高斯平面直角坐标系中,以纵坐标线北端按顺时针方向量到一直线的角度称为该直线的( )。
【单选题】在讨论铅酸蓄电池结构时,甲说:12V 蓄电池由6个单格电池并联组成;乙说:12V蓄电池由6个单格电池串联组成。你认为( )。
【单选题】选择正确的选项补全对话 ---Has Sam finished his homework yet? ---No, He ____________(finish) it.