铜片腐蚀试验主要是定性地检查试油中是否含有腐蚀金属的活性硫化物或游离硫。()
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保存测苯胺点所使用的苯胺时加入氢氧化钾的目的是防止苯胺氧化。()
GB/T1792电位滴定法测定馏分燃料中硫醇硫含量的原理是:硝酸银与硫醇反应,生成难溶的硫醇银沉淀,滴定终点由指示剂颜色转变来确定。()
11.abstractclassVehicle{publicintspeed(){return0;}}12.classCarextendsVehicle{publicintspeed(){return60;}}13.classRaceCarextendsCar{publicintspeed(){return150;}}......21.RaceCarracer=newRaceCar();22.Carcar=newRaceCar();23.Vehiclevehicle=newRaceCar();24.System.out.println(racer.speed()+,?+car.speed()25.+,+vehicle.speed());Whatistheresult?()
A. 0,0,0
B. 150,60,0
Compilationfails.
D. 150,150,150
E. Anexceptionisthrownatruntime.