小儿肺炎引起全身各系统病理变化的关键是缺氧、二氧化碳潴留。
参考答案：对
_______he is only 8 years old , he knows more about science than his father .
A．But
B．Though
C．So
D．Because
肺发育异常通常可分为3型，即__________、____________和____________。
