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 photographer 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.
ðeə hæz lɒŋ biːn ə ˌsjuːpəˈstɪʃən əˈmʌŋ ˈmærɪnəz ðæt ˈpɔːpəsɪz wɪl seɪv ˈdraʊnɪŋ mɛn baɪ ˈpʊʃɪŋ ðɛm tuː ðə ˈsɜːfɪs, ɔː prəˈtɛkt ðɛm frɒm ʃɑːks baɪ səˈraʊndɪŋ ðɛm ɪn dɪˈfɛnsɪv fɔːˈmeɪʃən. məˈriːn ˈstjuːdɪəʊ baɪˈɒləʤɪsts hæv ˈpɔɪntɪd aʊt ðæt, haʊˈɛvər ɪnˈtɛlɪʤənt ðeɪ meɪ biː, ɪt ɪz ˈprɒbəbli ə mɪsˈteɪk tuː ˈkrɛdɪt ˈdɒlfɪnz wɪð ˈɛni ˈməʊtɪv ɒv ˈlaɪfˈseɪvɪŋ. ɒn ði əˈkeɪʒənz wɛn ðeɪ hæv pʊʃt tuː ʃɔːr ən ʌnˈkɒnʃəs ˈhjuːmən ˈbiːɪŋ ðeɪ hæv mʌʧ mɔː ˈlaɪkli dʌn ɪt aʊt ɒv ˌkjʊərɪˈɒsɪti ɔː fɔː spɔːt, æz ɪn ˈraɪdɪŋ ðə baʊ weɪvz ɒv ə ʃɪp. ɪn 1928 sʌm ˈpɔːpəsɪz wɜː fəˈtɒgrəfə ˈwɜːkɪŋ laɪk ˈbiːvəz tuː pʊʃ əˈʃɔːr ə ˈwɔːtəlɒgd ˈmætrɪs. ɪf, æz hæz biːn rɪˈpɔːtɪd, ðeɪ hæv prəˈtɛktɪd ˈhjuːmənz frɒm ʃɑːks, ɪt meɪ hæv biːn bɪˈkɒz ˌkjʊərɪˈɒsɪti əˈtræktɪd ðɛm ænd bɪˈkɒz ðə sɛnt ɒv ə ˈpɒsəbl miːl əˈtræktɪd ðə ʃɑːks.
长期以来，海员中流传着一种迷信的说法，认为海豚会把快要淹死的人托到水面，救人性命；或在人们周围列队保护，使他们免遭鲨鱼伤害。海洋摄影室的生物学家指出，无论海豚多么聪明，认为它们有救人的动机可能是错误的。当它们偶尔把一个失去知觉的人推到岸边时，更大的可能是出于好奇或游戏，就像它们追逐被船首犁开的浪花一样。1928年，有人拍摄到了海豚像海狸一样把浸透水的床垫推上岸的情景。正如报道中所说，如果海豚保护人不受鲨鱼侵害，那么它们可能是出于好奇；而鲨鱼可能是闻到了可以美食一顿的香味。
任务配置：L0、L3、L4
知识笔记：
单词与短语
superstition/sjuːpəˈstɪʃən/
There has long been a superstition among 长期以来，。。。中流传着一种迷信的说法
credit sb with sth认为某人存在．．．
it is probably a mistake to ｄｏ ｓｔｈ认为。。。可能是错误的
have much more likely done it out of ｓｔｈ出于．．．做某事
as has been reported,如报道中所说
练习感悟：不是因为难所以不想练，而是因为不想练所以觉得难。