阅读下文，完成后面小题。
                                                                                          人类可以冬眠吗
                                                                                                     佚 名
         ①据科学调查，实际上，所有的动物在冬天都会由于低温的影响，变得不爱动弹。因为这时的食物非常缺乏，而身体又需要保存热量。
         ②在冬眠时，动物的体温会降到极低，它的新陈代谢、氧气需求和呼吸也会大大减少。不过，大部分动物都不会一直这样沉睡下去。它们会偶尔起来上个厕所、吃一些食物，或者伸展一下身体，来保证肌肉不会萎缩。
        ③有记录表明，在某些特殊情况下，人类也能够进入冬眠一样的状态。2006年10月，一位日本人在攀爬雪山时失踪，24天后才被救援人员发现。他被发现的时候，医生确定他身体的新陈代谢已经处于停滞状态。但他确实只是“睡着了”，经过治疗，成功地复苏过来。
        ④还有一名掉入冰水中的挪威滑雪者，当时他已没有了心跳和呼吸，体温下降到了13.8℃，但经过抢救，他仍然成功苏醒和复原。可见，人类自身还是具备冬眠的“潜力”的。
         ⑤人们还发现，当受伤的人进入冬眠状态后，就像被麻醉了一样。不但感觉不到疼痛，而且还可以减少出血，为抢救赢得宝贵的时间。目前，医生们已经可以用各种急救设备来降低病人的体温，以便外科医生能更顺利地为他们进行手术。
        ⑥但是，让人类“冬眠”的计划还很复杂。
        ⑦首先，咱们人不像动物，天冷了，咱们只要穿上厚衣服就可以照常活动了，就不需要窝在被窝里睡大觉了。久而久之，人类的冬眠“潜能”也就慢慢“退化”了。其次，单纯地用低温来让人冬眠其实是不行的。因为当温度降低到一定程度时，人体内的细胞就会被破坏，体内的血液和其他液体也会开始凝固，这一“睡”可能就再也醒不过来了。
         ⑧所以，现在用来使人进入冬眠状态的手段，实际跟麻醉差不多，需要使用一定的药物，而到目前为止，这种办法只能使体型较小一些的动物进入冬眠。对体型较大的动物来说，药量小了不起作用，药量大的话又极容易引发危险。
        ⑨至今科学家们还未能成功地在猪、羊等动物身上实现“人工冬眠”。现在人类对冬眠技术的需求主要集中在太空旅行方面。为了飞往更遥远的星球，宇航员需要暂时进入一种休眠状态，以便在沉睡中度过几年甚至几十年的漫长时间。否则，到达那些陌生星球的，只能是机器人了。因此，人类仍然在继续努力探索冬眠的秘密，争取在这一领域实现突破。
                                                                                                                                                                                          （选自《探索与发现》2014年4月，有改动。）

    Angela a 28-year-old Canadian, was driving to visit friends in another city 800 kilometres away. Her kids, 5-year-old Lexi and 10-week-old Peter, were fed and the car was1 with all the necessities for a road trip: toys, milk powder and snacks.

    The long journey had begun to2Peter, who started to cry. Angela inserted a nursery rhyme CD into the stereo and hoped it would help3him down. The soft music had a4effect. In no time, both children became5. Angela's eyes 6too, for just a few seconds.

    When Lexi suddenly woke up, she found it was7. Airbags obsured (遮挡) all the windows. Lexi's neck hurt and Peter was crying loudly. She pulled the handle of the door, but the door was8. Turning onto her side, Lexi kicked at the door9it flopped (猛地打开) open.

    That's when Lexi 10 her mother in the front seat. She tried to wake her up but Angela didn't11. At that time Lexi found their car was on a steep hill and it was kept from12by a large tree.

    Her shoes had come off, but Lexi felt no13as she climbed over glass and rocks up the embankment (路堤) to the14her mother had driven off.

A driver was traveling on the highway15he saw a tiny child jumping up and down,16her arms, crying for help. He pulled over, and the child told him her mother needed help. The driver looked around but saw17. The barefoot child pointed to the destroyed car downhill. Without 18, he ran down the hill. Twenty minutes later, an19came. Angela was rushed to the hospital.

    Later that year, the Royal Canadian Humane Association awarded Lexi a Bronze Medal for20.

指出下列四条食物链中，正确的是（  ）