Her voice was shockingly loud. "Put the chair down," she brayed.她的声音大得吓人。“放下椅子，”她粗声说道。Shockingly, this useless and dangerous surgery did not end until the 1930s.令人震惊的是，这种既无效又危险的手术直到20世纪30年代才被废止。His memory was becoming sh...
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...