1 . 哺乳类
mammalogy 哺乳动物学mammals哺乳类mammary cancer 乳癌
2 . 哺乳类动物
All mammalsbreathe air ., 哺乳类动物全都呼吸空气.
3 . 哺乳动物中
because among mammalsare many that vary their body temperatures during hibernation ., 因为在哺乳动物中有很多在冬眠的时候提问产生变化.
4 . 哺乳纲
mammalia 哺乳纲mammals哺乳纲mammatus cloud 乳房状云