食品安全法对未经许可从事食品生产经营活动，或者未经许可生产食品添加剂的违法行为所应承担的法律责任是如何规定的？
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有自然发火可能性的矿井，主要运输巷道应布置在（）内，并采用预防性灌浆或者其他有效预防自然发火的措施。
A. 岩层
B. 煤层
C. 矿层
D. 采空区
In a chilled water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by （）.
A. increasing refrigerant pressure in the coil
B. increasing chilled water flow through the cooler
C. sub-cooling the refrigerant in the condenser
D. superheating the refrigerant in the compressor
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