练习材料：
Lesson 18-1 Porpoises
There has long been a superstition among mariners that porpoises will save drowning men by pushing them to the surface, or protect them from sharks by surrounding them in defensive formation. Marine Studio biologists have pointed out that, however intelligent they may be, it is probably a mistake to credit dolphins with any motive of lifesaving. On the occasions when they have pushed to shore an unconscious human being they have much more likely done it out of curiosity or for sport, as in riding the bow waves of a ship. In 1928 some porpoises were photographed working like beavers to push ashore a waterlogged mattress. If, as has been reported, they have protected humans from sharks, it may have been because curiosity attracted them and because the scent of a possible meal attracted the sharks.
应用配置：L0+L4
知识笔记： superstition/ porpoises / drowning/ formation/ intelligent/ dolphins/ unconscious/ waterlogged/ mattress/
练习感悟：用时53分。今日语感不行，喉咙也有些嘶哑，状态不佳，呈现的结果也不是太完美。
