自发性气胸的常见原因不包括（）。
A.肺结核
B.肺癌
C.肺大疱
D.COPD
E.用力咳嗽、屏气、喷嚏
参考答案：E
Ten years ago the population of our village was _____that of theirs. [ ]
A. as twice large as
B. twice as large as
C. twice as much as
D. as twice much as
民用建筑内设置在公共场所的消防广播扬声器，其功率不应小于（）W。
A.2
B.3
C.1
D.5
