—How old is Steve?

—He is ____________ and he has an ___________ sister.

A．13-year-old; 10 years old

B．13 years old; 11-year-old

C．13 years old; 10-years-old

D．13-years-old; 11-years-old

大型养路机械采用的BF12L513C型柴油机其中的“12”表示（）。

A、序列数

B、气缸直径

C、活塞行程

D、气缸数