慢性支气管炎并发肺气肿的主要症状为()
A.突然出现呼吸困难
B.逐渐加重的呼吸困难
C.窒息
D.发绀
E.心悸
参考答案:B
This is a good piece of music for us to _____. [ ]
A. dancing
B. dancing to
C. dance by
D. dance to
松驰