《招标投标法》规定，招标投标活动( )环节的最基本要求和特点是公开，保障所有投标人的知情权。
A．招标
B．投标
C．评标
D．开标
参考答案：D
— I telephoned him twice and I couldn't get through to him.
— I think that the line might have been out of order, ______? [ ]
A. don't you
B. wasn't it
C. do you
D. hadn't it
鼻导管吸氧，插导管前应将导管润滑，正确的方法是()
A．涂液状石蜡油
B．涂凡士林油
C．蘸20%肥皂水
D．蘸水
E．蘸50%乙醇
