新生儿肺透明膜病的病因是（）
A.肺泡发育不成熟
B.缺少肺泡上皮细胞
C.肺泡张力过高
D.代谢性酸中毒
E.缺少肺泡表面活性物质
参考答案：E
There are many shows during the Shanghai Expo.Is the UK Pavilion________you want to watch a play?[ ]
A. that
B. where
C. which
D. as
雌激素
A．胎先露B．胎产式C．枕先露D．胎姿势E．胎方位
