【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。
【多选题】随机试验的每一个可能结果,称为随机事件,根据事件能不能再分可以把事件分为( )。
【单选题】—_____ did he become a football player? —He became a football player in 1990. [ ]