题干

医生在治疗感染H7N9病毒的患者过程中,发现抗病毒药物对一些重症患者很难起作用,研究证明H7N9病毒已出现变异.下列对这一现象的解释中正确的是(  )

A:抗病毒药物选择使有耐药变异的H7N9病毒留下来

B:H7N9病毒的耐药性永远都是有利的

C:抗病毒药物的质量越来越差

D:H7N9病毒的繁殖速度越来越快

上一题 下一题 0.0难度 选择题 更新时间:2017-12-12 12:02:10

答案(点此获取答案解析)

A

同类题3

阅读下面文言文(选段),完成下列小题。

       宋学士濂,洪武①中以文学承宠渥②最久,后以老致仕③,每值万寿节④则来京贺,上与宴,恩数犹洽⑤。一日,与登文楼,楼峻,陟⑥级踬⑦焉。上日:“先生老矣,明年可无来。”濂稽首⑧谢。至明年万寿节前数日,上曰:“宋先生其来乎?”盖忘前语也。久之不至,曰:“其阻风乎?”使使视之江口,不至。日:“其有疾乎?”使使视之家,濂方与乡人会饮赋诗。上闻大怒,命即其家斩之。已而,入官。上食,孝慈⑨命左右置蔬膳于侧,上问:“后何为食蔬?”日:“闻宋先生今日赐死,故为蔬食,以资冥福o。”上感悟,遽起,命驾前双马驰赦之,日:“不及罪死。”会前使阻风钱塘江,稍得延,后使至则已绑至市矣,宣诏得免。久之,其孙慎⑩获罪,复执来京,将杀之。后复力救曰:“田舍翁请一先生尚有终始,濂教太子诸玉》珂无师傅之恩?且濂居家,必不知情。”乃免。

(选自明·王鏊《王文恪公笔记》,有删减)

     【注】①洪武:明太祖(朱元璋)年号。②宠渥:皇帝的宠爱与恩泽。③致仕:交还官职,即辞官。④万寿节:古代君主的生日。⑤恩数犹洽:依然蒙受皇恩j⑥陟:登。⑦踬:跌倒。⑧稽首:跪拜礼,常为臣子拜见君主时所用。⑨孝慈:即孝慈皇后,明太祖朱元璋的结发妻子。⑩冥福:迷信的人指死者在阴闽所享之福。⑩慎:人名,指宋慎。

同类题5

根据短文内容, 从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Most drinks stating that they are fruit flavored contain no fruit at all, while most of the rest contain only a small quantity of fruit, according to a study carried by the British Food Commission.

    "Shoppers need to check the labels before buying drinks, though sometimes the actual content can be nonexistent," said Food Commission spokesperson Ian Tokelove. "Food production is highly competitive. ____ It will increase profits, and consumers won't always realize they are being tricked."

    Flavorings are focused on the flavors of natural food products such as fruits, meats and vegetables, or creating flavor for food products that do not have the desired flavors. Researchers analyzed the contents of 28 strawberryflavored products sold in stores.____ Of the 11 products that did contain strawberries, five of them contained less than one percent real fruit. In addition, each juice box contained nearly eight teaspoons of sugar.

    ____ Let's take jam as an example. Some strawberryflavored jam was labeled as containing no artificial color1 s, flavors, or sweeteners, but it contained ly no strawberries at all.

    ____ Consumers have the rights to know clearly about what they have bought. Under current UK law, food packages do not have to distinguish between natural and artificial flavoring. "Describing a product as strawberry flavor and covering the surface of the packet with pictures of strawberries is misleading.____ Unfortunately, it is also legal and widespread," Tokelove said. "It's time to take measures to protect the consumers' rights."

A. They found that about 60 percent of them didn't contain any fruit at all.

B. Even products advertised as more natural often contained no fruit.

C. The products which contain real fruit are popular with people.

D. Actually the product contains just a tiny percentage of strawberry or even no fruit at all.

E. It is important and necessary to demand a small amount of flavoring in the products.

F. If companies can cut their costs by using flavoring, they are likely to do so.

G. The Food Commission suggested all flavors used in a product should be listed on the packaging.