我国已形成由（）组成的多层次股票市场体系。
A.期货市场
B.股指期货市场
C.创业板市场
D.柜台市场
E.主板市场
参考答案：C, D, E
筛漏斗的内界为（）。
A.筛泡
B.钩突
C.上颌窦开口
D.额隐窝
E.额骨鼻突
Which statement about transmitting distress messages by radiotelephone is INCORRECT?（）
A.Distress messages should first be transmitted on 2182 kHz
B.It is advisable to follow a distress message on 2182 kHz by two dashes of 10 to 15 seconds duration
C.If no answer is received on the designated distress frequencies，repeat the distress call on any frequency available
D.Channel 16 (156.8 MHz) may be used for distress messages
