【判断题】当非手性的分子经反应得到的产物是手性分子,则必定是外消旋体。
【单选题】So confused _____ that he didn’t know how to start his lecture. A. since he became B. would he become C. that he became D. did he become
【单选题】The little boy is crying at first, but at last, he become ______.
【单选题】When did he become President of the United States?
【判断题】当非手性的分子经反应得到的产物是手性分子,则必定是外消旋体。
【单选题】—_____ did he become a football player? —He became a football player in 1990. [ ]
【单选题】下列关于心表面的沟的描述中,说法错误的是( )