阅读杨国力的《仿生食品的肉丸风波》（有删改）一文，完成后面小题。
         ①2014年12月12日，央视新闻频道《共同关注》栏目曝光了南宁市淡村农贸市场的牛肉丸里暗藏猫腻，品种繁多的牛肉丸价格存在天壤之别。这是为什么？
         ②火锅，在中国是传统的冬季美食。火锅中不可缺少的食材便是丸子，其美味又实惠，并且种类繁多，有牛肉丸、虾丸、贡丸、蟹丸……根据含肉量的多少将肉丸分为特级、优级和普通级三级，特级的含肉量要求大于65%，优级的含肉量要大于55%，而普通肉丸的含肉量则要求大于45%。此外，三个等级的淀粉含量分别是特级不高于6%、优级不高于8%和普通级不高于10%，这类肉丸被称为“真肉丸”。
         ③然而，很多消费者都买超市现成散装的丸子，种类繁多的丸子使人“乱花渐欲迷人眼”，与原料肉相比，同等分量的肉丸却便宜很多，口感筋道、浓香的肉味，很是诱人，远比自己在家里做得好吃，如此实惠味美的肉丸便成为消费者火锅中的主角。从食品加工工业方面看，这类风味丸子可以称为“仿生食品”。
         ④仿生食品是通过食品技术手段用普通食品原料和食品添加剂模拟天然食品的营养、风味和形状，不仅扩大了食物的多样性，提高了畜产品和海产资源的综合利用和经济效益，也让消费者品尝到更丰富的口感，满足不同的需求，通过营养强化弥补天然食品中存在的营养缺陷。仿生食品大多使用淀粉、大豆蛋白，使用或不使用肉糜，再添加一些调味剂，根据不同需求添加或减少相应的原料，既能满足消费者的需求，又能改善消费者身体情况，所以从某种意义上来看，仿生肉丸不仅安全，并且营养丰富、健康美味。
         ⑤然而，目前仿生食品还没有统一的国家标准，加上市场竞争压力大，为了获取更多的利润，不良商家随意使用劣质原料，为了获得更好的口感和更长的保质日期，过量添加食品添加剂，使得本该是健康的食品变成过街老鼠。另外仿生肉丸在运输、销售过程中有时暴露在空气中，虽然冷藏，但是很容易受到空气中微生物的污染及交叉污染。
         ⑥丸子不论是不是真的有肉，仿生丸子能不能吃跟食品安全没有必然的关系，关键是仿生丸子在生产、物流、销售的过程中是否安全。明确这一点，消费者便可放心大胆选购符合自己风味的火锅丸子，过一个温暖的冬季。

                                                                                                                                                              （选自《中国科学报》2015-01-07）

阅读理解

Don't talk to me; I'm busy with my iPhone

    Riding a London subway, a person from China will notice one major difference: in London, people do not look at each other. In fact, eye contact is avoided at all times. That's not rudeness—people are just too busy to bother looking.

    Busy doing what, you ask? Well, they're certainly not using the time for a moment of quiet reflection, nor are they reading a book. New technology has replaced quiet habits. Today the only acceptable form of book on the London underground is an e-book.

    Apple company must earn a fortune from London commuters. Since the iPhone was put on market in 2007, over 40,000 --- yes, that's 40,000 “apps” (programs downloaded for the iPhone) have been designed.

    Commuters love them because they are the perfect time-fillers. One “app”, called iShoot, is a game that features tanks. Another one, Tube Exits, tells passengers where to sit on the train to be closest to the exit of their destination. ISteam clouds the iPhone screen when you breathe into the microphone. You can then write in the “steam” on your phone screen.

    For those without an iPhone, another Apple product, the iPod, may be another choice. It's not just teenagers who “plug in” to their music --- iPods are a popular way to pass the time for all ages.

    And if games, e-books and music aren't enough to keep you occupied. Then perhaps you would prefer a film. The development of palm DVD technology means many commuters watch their favorite TV show or film on the way to work. With all this entertainments, it's amazing that people still remember to get off the train.

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