发现气管插管患者有分泌物、痰或血块阻塞导管时，应立即（）

A.吸痰

B.止血

C.调高氧浓度

D.禁食

E.拔除气管插管

--- Thomas does well in dancing. How about Bob?

--- Bob is_____, I think. He once won the first prize in a dancing competition.

A．well

B．better

C．worst

D．bad