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....
经济学家警告，迫使人们向西部迁移的压力可能会增至很大的程度。Economists warn that enormous pressures could build up, forcing people to emigrate westwards.南部的种植园主买下了向西部迁移的小农的土地.Planters in the South bought land from small farmers who moved farther west...