男性,24岁,溺水后发生急性呼吸窘迫综合征。在呼吸室内空气时,血气分析显示: pH7.50,PaO248mmHg,PaCO228mmHg。面罩吸80%的氧气后复查动脉血气,结果为pH 7.50,PaO253mmHg,PaCO229mmHg。此患者发生低氧血症最主要的原因是
A. 气道阻力增加
B. 肺内分流(右向左)
C. 氧耗量增加
D. 低通气
当神经冲动到达运动神经末梢时,可引起接头前膜的
A. Na+通道关闭
B. K+通道开放
Ca2+通道开放
D. Mg2+通道开放
Wilson:Hello,may I speak to Peter Peter:().
A. Sorry, the number is engaged. Will you hold
B. Yes, speaking.
C. Hello,who're you,please
D. Hello, thank you for calling.
Rebecca:(). Dora: Really Well, personally, I think he wears the wrong colors. Actually light colors don~t really suit him.
A. I don't think Bob has chosen the right suit.
B. I love the way Bob dresses. He always looks so smart.
C. How funny Bob looks in that jaeket!
D. Boh's new coat looks very expensive.