any warm-blooded vertebrate having the skin more or less covered with hair; young are born alive except for the small subclass of monotremes and nourished with milk
造句
用作名詞(n.)
Man and most other mammals are viviparous. 人和其他大多數(shù)哺乳動物都是胎生的。
Among mammals whales have the greatest mass. 哺乳動物中以鯨魚最大。