单项选择题
A.3000B.300C.2000D.1500
A.停止卸液,切断排液阀B.停止卸液,切断进液阀C.停止排液,切断排液阀D.停止排液,切断进液阀
A.20m,20.12mB.20m,21.24mC.20.12m,20.24mD.20.12m,21.24m