A young man sees a sunset and, unable to understand or express the emotion that it ______ in him, concludes that it must be the gateway to a world that lies beyond.

A．spend some time resting
B．close their eyes when sleeping
C．are good sleepers
D．are poor sleepers

A．these animals rarely need any rest
B．they almost always keep alert to danger
C．they often stay awake
D．their eyes are rarely closed even when they are asleep