The lowest temperature required to cause self-sustained combustion of a substance independent of any outside source of ignition is called （）. ["explosive range","flash point","ignition temperature","combustion temperature"]
Contracts whereby the possession and control of a ship vest（）the Charterer are becoming more common today especially in the oil tanker trade. ["on","to","at","i"]
LKJ2000型监控装置“轮对空转”抑制时间（）秒。
真核生物经转录作用生成的mRNA是：（） ["单顺反子","多顺反子","内含子","插入序列"]
If a refrigeration compressor will not start, the reason may be （）. ["the pressure regulating valve is not closing","an excessive lack of refrigerant in the system","badly leaking discharge valves","worn piston ring"]
合格证班计划保留时间为（）。
