–I am so sorry to have come late for the meeting.

-It’s not your fault. With                   rush-hour traffic and              heavy rain, it is no wonder you were late.

A．a; a

B．the; the

C．/; /

D．/; a

相交形成支气管镜检查重要标志气管隆嵴是（）。

A.气管

B.左、右主支气管

C.肺叶支气管

D.肺段支气管

E.环状软骨