词汇	a vein of coal
释义	a vein of coal 煤层
随便看	double primary double primary and back-up protection double primary cancer double primary cancers double primary carcinoma double primary lung cancer double primary runner double-primary thoracic-diseases double-primary thoracic-dlsease double prime double-prime double primer method double-primer method doubleprimer PCR Double-primer PCR double prime sequences double-prime sequences Double Principal-Agent Double Principal Mode double-principal theory double principle double principle-agent theory double print double print down double printed board