口唇发绀，吸气时出现“三凹征”，应考虑为（）
A.气管阻塞
B.慢性支气管炎
C.支气管哮喘
D.慢性阻塞性肺气肿
E.支气管扩张
参考答案：A
— The contest is so easy, but you fail to pass it.
— I'm sorry it ______ be this way. [ ]
A. need
B. should
C. may
D. would
债券按照其券面形态可分为( )。
A．凭证式债券
B．记账式债券
C．附息债券
D．实物债券
