Many children      your age are always      a good mood to do what they’re interested in.

A．at, in

B．of, in

C．at, on

D．of, with

( )是指劳动者在劳动时的能量消耗量与安静时的能量消耗量之差除以劳动时间。

A．基础代谢率

B．能量代谢率

C．劳动代谢率

D．劳动强度指数