碳的诸多同位素the many isotopes of carbon碳的化合价是4价。Carbon has a valency of 4.通过环氧化和氧化就得到外消旋的含十八个碳的昆虫返动激素.Epoxidation and oxidation gave the racemic C 18 - juvenile hormone....
The family are rich, and extremely sophisticated and cosmopolitan.这家人很富有，老于世故，而且见多识广。She 's a real cosmopolitan.她是个真正的世界主义者。Alexandria's population was cosmopolitan, but mainly Greek.亚历山大市的居民来自世界各地, 但以希腊人居多....