If the firefighters _____ in time, the fire would have resulted in many deaths in the hotel. [ ]

A. wouldn't have arrived

B. hadn't arrived

C. didn't arrive

D. shouldn't arrive

“外热动物”依靠“晒太阳”提高体温，主要是依靠（）

A．可见光中的蓝紫光，因为短波光能量多

B．可见光中的绿光，因为绿光植物不吸收

C．可见光中的红光和可见光外的红外光，因为红光和红外光具有热效应

D．可见不名的各波长的光都含有能量，所以是等价的