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....
Mexican cookery is economical, she says. Nothing goes to waste.“墨西哥的烹调注重俭省，”她说，“任何东西都不会浪费。”She took me to a Mexican restaurant.她带我去了一家墨西哥餐厅。It was dubbed into Spanish for Mexican audiences.它被译制成西班牙语以方便墨西哥观众观看。...