CO2具有一定的渗透和环绕能力，因而扑救甲类火灾时不易发生复燃。
In most cases，the mere reception or dumping down of the cargo on the ship（）involve completion of loading，because the operation of loading involves all that is required to put the cargo in a condition in which it can be carried． ["is not","has not","do not","does not"]
发生火灾后应采取的最初步骤是立刻发出警报。
In a charter-party，the amount of despatch money payable is often fixed（）. ["at one fourth the demurrage rate","at one third the demurrage rate","at half the demurrage rate","at the demurrage rate"]
什么是起升机构制动器失灵？
起升机构制动器失灵天车工如何处理？
