鉴别先天性喉蹼与先天性喉喘鸣的要点是()
A．呼吸困难的程度
B．有无声嘶
C．是否出生后应出现症状
D．是否需要治疗
E．吞咽困难
参考答案：B
In societies where social roles are determined, boys usually copy the behavior of their fathers, and girls usually also copy _____ of their mothers.
A．that
B．those
C．one
D．the ones
食用______可引起含氰甙类食物中毒。
A．马铃薯
B．山药
C．四季
D．李子仁
