The entire memo took up all of two pages.整个备忘录写了满满两页纸。This memo could be the smoking gun that investigators have been looking for.这份备忘录可能是调查人员一直在寻找的证据。She penned a short memo to his private secretary.她给他的私人秘书写了一份简短的备忘录。I...
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.阳离子表面活性剂通常为季铵盐类.Cationics are usually quaternary ammomium salts.反 离子通常是钠, 钾和铵.The usual counter - ions are sodium, potassium an...