甲烷和丙烷是烷烃。Methane and propane are alkanes.丙烷气钢瓶a propane gas cylinder亚胺基杂环丙烷季铵盐的阳离子,一定是按协同反应的方式开环的.The aziridinium ions must all be opened by a concerted process....
Bob Beamon's longstanding record for the long jump was eventually broken.鲍勃·比蒙长期保持的跳远纪录最终被打破了.Longstanding poverty has been exacerbated by racial divisions.种族分化已经加剧了长期的贫困问题。In view of our longstanding business relat...
店里的一些地方十分肮脏不洁，简直就是滋生细菌的理想温床。Parts of the shop were very dirty, unhygienic, and an ideal breeding ground for bacteria.科学家认为,过度接触抗菌素使有抗药性的细菌的传播更广泛.Scientists believe overexposure to antibiotics helps resistant bacteria bec...