鲨鱼的行为动作: glide, move,twist, turn, bend, swim, hunt, bite,leap, catch, attack 鲨鱼的身体结构: tooth, tail fin, cartilage, skin, mouth, head,back,belty 鲨鱼牙齿的分类: long spiky tooth,flat tooth, serrated tooth take one's place 代替某人;替换某人 watch out J心 go surfing 去冲浪 on purpose 故意地 be afraid to do sth害怕做某事 条件状语从句: Ifa shark loses a tooth, a new one moves forwardto take its place. 时间状语从句: The pups stay near the shallow water until they aregrown. 比较状语从句: Sharks can see better than humans can. 宾语从句: You can imagine how big the shark must have been. 过去分词短语作后置定语: Ahammerhead shark has a headshaped like a giant hammer.