肺源性的呼吸困难主要是由于()
A.肺通气、换气功能不良
B.肺活量下降
C.血中二氧化碳潴留
D.缺氧
E.以上均不是
参考答案:A, B, C, D
With exports ______ a big role in its economic growth, China has been affected by the current financial
storm.[ ]
A. playing
B. to play
C. played
D. play
在下列哪种气候区应重点解决住宅冬季的日照、防寒和保温问题()
A.Ⅰ、Ⅱ气候区
B.Ⅳ、Ⅴ气候区
C.Ⅱ、Ⅲ气候区
D.Ⅲ、Ⅳ气候区