肺泡与血液间的气体交换，血液中的氧气进入肺泡，同时肺泡内的二氧化碳进入血液___

基本分析与技术分析的理论依据和研究对象是一致的。（）

用反证法证明命题“在Rt△ABC中，若∠A=90°，则∠B≤45°或∠C≤45°“时，应先假设（）

A．∠B＞45°，∠C≤45°

B．∠B≤45°，∠C＞45°

C．∠B＞45°，∠C＞45°

D．∠B≤45°，∠C≤45°

小题1:I doesn’t like swimming.

小题2:She was about to go to bed then someone knocked at the door.

小题3:They walked towards the village with a boy led the way.

小题4:Dressing in a white uniform, he looks more like a cook than a doctor.

小题5:I am come from a small village.

小题6:My best friend is come next month.

小题7:This is the book who I lost last week.

小题8:Hurry up, and you’ll be late.

小题9:My best friend is angry at me. What should I do?

小题10:Please return back the book to me in time.  

请问：火车连续发出两声长鸣，这不表示（）

A.前进

B.停留

C.倒退

D.故障

中央处理器的重要作用是运算和显示。( )