结构中含有二苯并氮环为()
A．地西泮
B．卡马西平
C．盐酸氯丙嗪
D．苯妥英钠
E．苯巴比妥
参考答案：B
有最小的自然数，没有最大的自然数．______．（判断对错）
That day, we______ for the train station when Tom fell and hurt his legs badly.
A．have been leaving
B．were just about to leave
C．have left
D．are just going to leave
环为()
环为()