与左主支气管相比，右主支气管（）
A.细而长
B.粗而长
C.粗而短
D.细而短
E.呈水平方向走行
参考答案：C
---Isn’t that your teacher over there?
---No, it ______ be him. I’m sure he doesn’t wear glasses.
A．can’t
B．must not
C．won’t
D．may not
