whales and dolphins; manatees and dugongs; walruses; seals
双语例句
用作名词 (n.)
The membranes extend backward to encompass hind limbs that are quite a bit smaller than those of a terrestrial mammal of comparable body size. 翼膜向后延伸包围住后肢，蝙蝠的后肢比其他体形相当的陆栖哺乳动物明显小了许多。
