患者因咳嗽无力而排痰不畅，易导致（）。
A.窒息
B.肺不张
C.肺水肿
D.心力衰竭
E.呼吸困难
参考答案：A, B, E
已知角α终边经过点P（-2，3），则α的正弦值为______．
The mathematician Bruno was burned at the stake by the Church largely for supporting Copernicus'
theory, yet, a couple of centuries later, Copemican__________seemed harmless. [ ]
A. speakers
B. advocates
C. writers
D. theorists
