以下参数之间一一对应的为（）。
A.NSE---BSC
B.PVC---BTS
C.BVC---Cell
D.NSVC---MFS
参考答案：A, C
Parents should pay attention to the cases _______ their children have difficulty adapting to new surroundings.
A．where
B．as
C．why
D．when
婴幼儿易患呼吸道感染的主要原因是
A．鼻腔短小，狭窄，黏膜血管丰富B．呼吸道黏膜缺乏SIgAC．呼吸浅表D．呼吸频率快E．呈胸式呼吸
