Most direct substitution of groups bound to an aromatic nucleus is limited to diazonium salts.大多数连于芳核能被直接取代的基团仅限于重氮盐.Severe steric effects at the reactive carbon would impede the substitution.大的立体效应阻止在碳上的取代.We use saccha...
In my experience a straight substitution of carob for chocolate doesn'twork.根据我的经验，用角豆制品直接代替巧克力行不通。We use saccharin in substitution for sugar.我们用糖精代替糖.Substitution, No.3 for No.4.换人,4号下, 3号上....
Betoken : To be or give a sign or portent of.预示: 做或给出记号或预兆.He gave her a gift to betoken his gratitude.他送她一件礼物表示感谢.Dark clouds betoken a storm.乌云予示着暴风雨的来临.Those black clouds betoken rain.那些乌云预示有雨....
We need to find ways of dealing creatively and usefully with our feelings.我们需要找到一些既有创意又实用的方法来调整我们的情绪。In some cases the slag can be disposed of usefully.有时炉渣能有用处.We can usefully distinguish between four main kinds of inte...
The book's tone is refreshing, although its occasional passages of lazy journalese can be jarring.这本书的语调清新.尽管其中几段对懒惰新闻媒介的描写有点刺耳.Two of them had been jarring with each other.他们中的两个人一直在争吵不休.In the context of this chap...