I t doesn’t matter if _______ boys play basketball too much instead of watching TV.

A．sixteen-years-old

B．sixteen-year-olds

C．sixteen year old

D．sixteen-year-old

对给粉机进行清理或掏粉前，应将给粉机电动机的电源切断，挂上警告牌，并须注意防止（）煤粉伤人。

A.热；

B.着火的；

C.自燃的。