可引起支气管狭窄及闭塞的是()
A.异物
B.支气管癌
C.支气管周围肿瘤压迫
D.由感染造成的肉芽肿、瘢痕
E.支气管腺癌
参考答案:A, B, C, D, E
My boss______for Beijing in a few days. Do you know when his plane______?
A.leaves; takes off
B.is leaving; takes off
C.is leaving; is taking off
D.leaves; is taking off
便携式硫化氢气体检测仪的探头类型主要是()。
A、红外型
B、催化燃烧型
C、半导体型
D、电化学型