磁流体动力分选
参考答案：在磁场与电场的联合作用下，以强电解质溶液作为分选介质，按固体废物中各组分间密度、比磁化率和电导率的差异使不同组分分离的过程。
一层楼有10步楼梯，一栋大楼有17层楼，这栋大楼只有5个楼道．这栋大楼共有______步楼梯．
The star performer of comic dialogue is full of humor, who is able to ______an occasion whenever
_____ go wrong with his humorous performances [ ]
A. light up; things
B. brighten up; things
C. amuse; the things
D. entertain; things
