称一级支气管的是（）。
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
参考答案：B
选词填空。
1. This dress ____ (is, are) pretty.
2. We'll take ____ (it, its).
3. How much ____ (is, are) those big shoes?
4. Look ____ (at, for) that dress.
5. It fits ____ (I, me) well.
色淀
