吸气时肺内压下降。
参考答案:对
Every morning, he listens to English news_________ the radio.
A.from
B.on
C.in
D.to
下列哪项是脐带脱垂的发生率
A.0.1%~0.2%B.0.3%~0.5%C.0.4%~10%D.1%~8%E.4%