Little      about her own safety when trying to save the poor blind man, though she was in great danger

herself.   [ ]

A. did Rose care      

B. Rose did care      

C. Rose does care      

D. does Rose care

一台汽油机工作时的功率为P，在t时间内烧掉汽油的质量为m，如果汽油的热值

是q，则这台汽油机的效率是__________，这段时间做的额外功是__________。