To determine that a compartment contains sufficient oxygen to sustain life, you should use a/an （）. explosimeter。 oxygen indicator。 fresh air indicator。 all of the above。
下列焊接方法中，热影响区最窄的是（） 焊条（手工）电弧焊。 埋弧自动焊。 气焊。 电渣焊。
When fueling has been completed（）. the fuel tank fill pipe should be left open to allow vapors to vent from the tank。 the engine should be started immediately to prevent vapor lock in the fuel line。 all hatches should be opened and all compartments should be ventilated。 open the fuel line and drain a small amount of gasoline into the bilge to clear the line of sediment。
When fighting fires in spaces containing bottles of LPG (liquefied petroleum gas)，you should （）. attempt to isolate the fire from the LPG。 cool the bottles or remove them from the fire area。 see that the valves on all LPG bottles are closed。 place insulating material over the bottle。
在开展强制性产品认证过程中，以下哪些事宜不会因为认证申请人选择了不同的认证机构而产生差异（） 认证检测费。 工厂审查的人数。 认证证书的有效期。 认证标志的核准使用方式。
An oxygen indicator will detect （）.
