肺实质包含下述哪些成分（）
A.肺泡管
B.肺泡囊
C.小叶间隔
D.肺泡
E.肺泡壁
参考答案：A, B, D, E
There is no perfect person, some people have made _____success of themselves in spite of what would appear to be ______ weakness in their professions.
A．/, a
B．a, /
C．a, a
D．/, /
对绞车信号装置有哪些要求？
