气管插管术之关键是（）
A.吸入纯氧，过度换气
B.应用足量肌松剂
C.消除咽喉反射气管插管反应
D.避免牙齿和气道损伤
E.显露声门
参考答案：E
—The coat is beautiful. How much did it ______?
—I ______ 98 yuan on it. [ ]
A. cost; spent
B. pay; cost
C. spend; paid
D. cost; paid
不属于群落成员型的是( )。
A．优势种 B．建群种 C．特有种 D．亚优势种
