简述石油沥青制成液体石油沥青的过程?
液体石油沥青宜采用针入度较大的石油沥青,使用前按先加热沥青后加稀释剂的顺序,掺配煤油或轻柴油,经适当的搅拌、稀释制成。
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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