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今年政府工作报告中指出,2017年发展的主要预期目标是:国内生产总值增长6.5%左右,说明我国工作中心已不再是经济建设。
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病毒的话

   我们家族的名称是“病毒”。顾名思义,就是能致病的毒物。因此,人们谈病毒色变。可是,这不能赖我们呀!是你们人类给我们起了这么一个不雅的名称。

   我们也不好怪人类,给我们起这个名称也是有来由的。19世纪末,烟草得了花叶病;荷兰植物学家比林杰克把病的烟叶捣碎,挤出液汁,用没有上釉的瓷过滤器过滤,滤过的液汁用当时最好的显微镜都检查不出有什么细菌,可是它仍然能让烟草得病。比林杰克认为,这一定是比细菌还小的微粒在作怪。他把这类微粒叫做“病毒”,人类就是这样结识了我们。后来发现,人类许多疾病,如流感、麻疹、肝炎等等,其罪魁祸首也都是我们。把我们称作病毒就更有理由了。

   人类的本事越来越大,科学家终于看到了我们的真面目。我们家族最小的成员只有细菌的千分之几那么大,直径只有百万分之一厘米,大的也只有百万分之二十五厘米。(A)我们的构造比细菌还简单的多。我们根本没有细胞结构,只不过是由一个核酸分子(一种记录遗传密码的物质)外包一层蛋白质外壳而已。

   其实同世界万物一样,我们之中有有害的病毒,也有有益的病毒。

    20世纪初,科学家就发现,我们家族中有些成员有孙悟空钻进铁扇公主肚内的本领,能钻进细菌体内,在那里繁殖,使细菌死亡,科学家把它们叫做“噬菌体”。(B)人种了牛痘可以产生对天花的免疫力,牛痘就是经过“改造”后毒性减弱的天花病毒。经过这一番改造,它不仅不再危害人类,还反戈一击,帮助人类消灭这种可怕的传染病。现在许多种疾病的病毒已经被用来制造疫苗为人类服务了。我们家族中还有一些成员叫做“肠道腐生病毒”。它们在婴儿出生以后不久就进入婴儿肠道,在人一生中始终呆在那里。其中有些是有益的。它们可以促进人体产生有防治疾病作用的干扰素,抑制能致病的肠道病毒、流感病毒等等。科学家现在已经制成活肠道病毒、流感病毒等等。科学家现在已经制成活肠道病毒疫苗,它能预防多种传染病,甚至还有一定的抗癌作用哩!

同类题4

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    Five meteorologists (气象学家) who were trapped for two weeks after polar bears surrounded their weather station are now able to leave after the creatures were chased away. Their supervisor told NBC News early Wednesday.

    Russian officials had feared the siege could last for another month, the time it would take to reach the islands in the Kara Sea, high in the Arctic Circle. But on Tuesday night a research ship took a detour (绕道) to assist those weathermen, station supervisor Vasily Shevchenko told NBC News. The ship run by Russia's state-run oil firm Rosneft frightened away the bears using its helicopter, before resupplying the weather station with more food and puppies (幼犬) . The puppies are not yet big enough to deter the bears, but the station is planning to draft in a replacement adult guard dog as soon as possible.

    Some of the bears had taken to sleeping directly outside the windows of remote outpost. There was no risk of the researchers starving because they had a year's worth of food, but they were forced to take dangerous trips to a nearby building, holding a gun for protection, according to Shevchenko.

    Polar bears are an endangered species. In Russia, it's a crime to shoot them unless in self-defense. The bears usually leave the islands in the summer, but this time they were trapped by the melting ice, an apparent sign of climate change, according to Shevchenko. “They've stayed on the island because there is nowhere for them to go,” he said.

    The animals suffer from global warming because it shrinks the floating ice that forms their main hunting ground. According to the environmental group the World Wide Fund for Nature, known as the WWF, this has got some polar bears to go near human habitats in search of food.