海牛的行為動作: swim,roll,do somersaults,migrate,breathepush, sleep, rest, float 海牛進食的動作: nibble,graze, munch,eat, grind,drink,swallow 海牛的外貌特征: gray,wrinkled,mighty,big,heavy,large 海牛的身體結構: whisker, skin, tail, eye,nostril,flipper, lip,molar 與海牛的生活習性有關的詞: mammal,super swimmer,shallowwater, ocean, river, warm water, herbivore, near the surface be similar to...與......相似 teach sb.how to do sth.教某人怎樣做某事 take a breath 吸氣 on one'sown 靠自己的力量，獨自地 atatime每次 定語從句: Manatees are mammals that live in the water. 比較狀語從句: That's as long as two kids'bikes lined up endtoend. 被動語態:Amanatee baby is called a calf 動名詞短語作主語: Swallowing trash can hurt manatees 結果狀語從句: Fishing line can get tangled around manatees sothey can't swim.