She watches him plane the surface of a walnut board.她看着他刨平一块胡桃木板。The stool comes in several sizes in walnut or mahogany.凳子有几种尺寸，材质分胡桃木和红木两种。Black walnut is extremely sensitive to damage from late spring frosts.黑胡桃对春天晚霜的危...
通常阳离子交换量随破裂增加而增大.Cation exchange capacity generally increases with an increase in broken bonds.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.溴、氯阳离子化合物的数量受局限.The number of ca...