维持胸内负压的必要条件是
A．胸膜腔密闭状态
B．呼吸肌收缩
C．胸廓扩张
D．呼吸肌舒张
E．呼吸道存在一定阻力
参考答案：A
根据句意和汉语注释，写出单词的正确形式。
小题1:--- I’ll go to the supermarket. Let me get you some fresh vegetables.
--- Thanks for your ______ (提议). It’s kind of you.
小题2:Some tourists from China were robbed in a ______ (拥挤的) street in Paris on March 20.
小题3:I ______ (推断) that Miranda would go to watch the drama.
小题4:I don’t want to go out tonight, and ______ (总之) I haven’t got any money.
播种机的播种质量评价指标
