A．waterB．oxygenC．energyD．heat

We have made a （an）try to carry out the plan.A.attemptB.effortC.energyD.source

材料题请点击右侧查看材料问题 查看材料A.waterB.airC.ener

材料题请点击右侧查看材料问题 查看材料A.waterB.liquidC.m

Which fire fighting agent has the greatest capacity for absorbing heat？A.waterB.dry chemic

A centrifugal pump can’t supply water after startingYou should check ____.A.priming waterB

61._________A. waterB. airC. energyD. safety