练习材料：
Modern cavemen Part-2
ˈmɒdən ˈkeɪvmən pɑːt-2
现代洞穴人
The deepest known cave in the world is the Gouffre Berger near Grenoble. It extends to a depth of 3,723 feet. This immense chasm has been formed by an underground stream which has tunneled a course through a flaw in the rocks. The entrance to the cave is on a plateau in the Dauphine Alps. As it is only six feet across, it is barely noticeable. The cave might never have been discovered has not the entrance been spotted by the distinguished French pot-holer, Berger. Since its discovery, it has become a sort of potholers' Everest. Though a number of descents have been made, much of it still remains to be explored.
A team of pot-holers recently went down the Gouffre Berger. After entering the narrow gap on the plateau, they climbed down the steep sides of the cave until they came to narrow corridor. They had to edge their way along this, sometimes wading across shallow streams, or swimming across deep pools. Suddenly they came to a waterfall which dropped into an underground lake at the bottom of the cave.
ðə ˈdiːpɪst nəʊn keɪv ɪn ðə wɜːld ɪz ðə Gouffre ˈbɜːgə nɪə Grenoble. ɪt ɪksˈtɛndz tuː ə dɛpθ ɒv 3,723 fiːt. ðɪs ɪˈmɛns kæzm hæz biːn fɔːmd baɪ ən ˈʌndəgraʊnd striːm wɪʧ hæz ˈtʌnld ə kɔːs θruː ə flɔː ɪn ðə rɒks. ði ˈɛntrəns tuː ðə keɪv ɪz ɒn ə ˈplætəʊ ɪn ðə Dauphine ælps. æz ɪt ɪz ˈəʊnli sɪks fiːt əˈkrɒs, ɪt ɪz ˈbeəli ˈnəʊtɪsəbl. ðə keɪv maɪt ˈnɛvə hæv biːn dɪsˈkʌvəd hæz nɒt ði ˈɛntrəns biːn ˈspɒtɪd baɪ ðə dɪsˈtɪŋgwɪʃt frɛnʧ pɒt-ˈhəʊlə, ˈbɜːgə. sɪns ɪts dɪsˈkʌvəri, ɪt hæz bɪˈkʌm ə sɔːt ɒv ˈpɒthəʊləz ˈɛvərɪst. ðəʊ ə ˈnʌmbər ɒv dɪˈsɛnts hæv biːn meɪd, mʌʧ ɒv ɪt stɪl rɪˈmeɪnz tuː biː ɪksˈplɔːd.
ə tiːm ɒv pɒt-ˈhəʊləz ˈriːsntli wɛnt daʊn ðə Gouffre ˈbɜːgə. ˈɑːftər ˈɛntərɪŋ ðə ˈnærəʊ gæp ɒn ðə ˈplætəʊ, ðeɪ klaɪmd daʊn ðə stiːp saɪdz ɒv ðə keɪv ənˈtɪl ðeɪ keɪm tuː ˈnærəʊ ˈkɒrɪdɔː. ðeɪ hæd tuː ɛʤ ðeə weɪ əˈlɒŋ ðɪs, ˈsʌmtaɪmz ˈweɪdɪŋ əˈkrɒs ˈʃæləʊ striːmz, ɔː ˈswɪmɪŋ əˈkrɒs diːp puːlz. ˈsʌdnli ðeɪ keɪm tuː ə ˈwɔːtəfɔːl wɪʧ drɒpt ˈɪntuː ən ˈʌndəgraʊnd leɪk æt ðə ˈbɒtəm ɒv ðə keɪv.
世界上最深的洞穴是格里诺布尔附近的高弗.伯杰洞，深达3,723英尺。这个深邃的洞穴是由一条地下暗泉冲刷岩石中的缝隙并使之慢慢变大而形成的。此洞的洞口在丹芬阿尔卑斯山的高原上，仅6英尺宽，很难被发现。若不是法国著名洞穴探险家伯杰由于偶然的机会发现了这个洞口的话，这个洞也许不会为人所知。自从被发现以后，这个洞成了洞穴探险者的珠穆朗玛峰，人们多次进入洞内探险，但至今尚有不少东西有待勘探。
最近，一队洞穴探险者下到了高弗.伯杰洞里。他们从高原上的窄缝进去，顺着笔直陡峭的洞壁往下爬。来到一条狭窄的走廊上。他们不得不侧着身子往前走，有时过浅溪，有时游过深潭。突然，他们来到一道瀑布前，那瀑布奔泻而下，注入洞底一处地下湖里。
任务配置：L0、L4
知识笔记：
单词与短语
extends to a depth of深达...英尺
barely noticeable很难被发现
wade across shallow streams过浅滩
at the bottom of在某处的底部
练习感悟：感觉每一篇新概念都在着重使用某些特定用法。