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...
Store the peppercorns in an airtight container and grind the pepper as you need it.将胡椒粒储存在密封容器中，在需要的时候磨成粉。Combine the stock, whole onion and peppercorns in a pan and bring to a simmer.将高汤、一整头洋葱和胡椒粒一起放在平底锅里，开小火炖。Tea. Bisc...