—Can I help you?

—I 'd like _____ for my twin daughters. [ ]

A. two pair of shoes

B. two pair of shoe

C. two pair shoe

D. two pairs of shoes

CRH3C型动车组采用机车救援时，由列车管向总风管充风需打开救援模式转换塞门（）阀。

A、Z05；

B、Z06；

C、Z30；

D、Z18。