deer是可数名词，但是单复同形，即单数是deer，复数也要写成deer。
deer n.鹿；复数： deer；
例句：
Its going to be the death knell of the red deer.
这将导致马鹿的灭绝。
相关介绍
Images of deer and hunters decorate the cave walls.
洞穴壁上装饰着鹿和猎人的画像。
The deer never became tame; they would run away if you approached them.
那些鹿一直没有被驯服：你一靠近，它们就跑开。
Observant walkers may see red deer along this stretch of the road.
观察敏锐的步行者可能在这一路段看到赤鹿。
