A hydrocarbon was known to be either an alkene or alkane.某碳氢化合物已知可能是烯烃或是烷烃.The hydrocarbon must be an alkene.这个碳氢化合物必定是烯烃.The betaine will collapse to the alkene only when these two functions are eclipsed.只有当这两个基团移至重迭位置时...
Berg tilts his head and a mischievous look crosses his face...伯格侧着头，脸上掠过一丝调皮的神情。Economists worry that this may be only the tip of the icecream - berg: inflation seems to resurgent.经济学家担心,这种现象也许只是“冰淇淋山”的一角: 通货膨胀似乎即将卷土重来.A...
救生艇倾覆，艇里的人被掀入水中。The lifeboat capsized, throwing the occupants into the water.我刚开始驾驶游艇航行时，艇上的汽油发动机老出毛病。I first started cruising in yachts with temperamental petrol engines.哈佛大学队领先4个艇位胜出。Harvard won by four lengths....