题干

近年来,由于抗生素的滥用致使细菌的抗药性越来越强.用达尔文的生物进化论分析,产生的主要原因是(  )

A:细菌为了适应环境,产生了适应环境的变异

B:抗生素选择了发生耐药性变异的个体使其生存下来

C:耐药性的细菌繁殖能力比不耐药性的细菌繁殖能力强

D:生产抗生素质量下降,使抗生素的杀菌能力下降

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答案(点此获取答案解析)

B

同类题4

阅读下面的文言文,完成文后各题。

给季弟书

    辛卯月日,客粤二旬。每念吾弟介然不苟,颇以远大相期,圣人所谓“刚毅木讷”,庶几近之;但刚为美德,吾弟却于此成一“疏”字,生一“褊”字,又渐流一“傲”字。

    往时我之督弟甚严,近五六年,见弟立志操行,颇成片段。每欲长养吾弟一段勃然挺然之气,不忍过为折抑,又我每有优柔姑息之病,吾弟常能直言正色、匡我不逮、隐吾畏友,凡细故偶失,多为姑容,使弟不生疑忌,矢直无讳。坐此两者,故今之督弟甚宽。然我此等即是姑息,欲归为弟畅言。

    弟与人执事,亦颇竭忠,每乏周详之虑;临事时患难险阻都所不避,而不能为先事之计,以为大节无损。诸细行杂务,不留心无大害,然因此失事误人,因以失己者多有之。此则所谓疏也。疾恶如仇,辄形辞色;亲友有过,谏而不听,遂薄其人;人轻己者,拂然去之;行有纤毫不遂其志,则抑郁愤闷不能终朝。此诚褊衷,不可不化。其人庸流也,则以庸流轻之;其人下流也,则以下流绝之;岸然之气,不肯稍为人屈。遂因而不屑一世,凌铄侪辈。长此不惩,矜己傲物、驯致大弊。夫疏则败事,褊则邻于刻薄,傲则绝物而终为物绝:三者皆刚德之害。然皆自刚出之,倘能增美去害,则于古今人中当自造一诣矣。子夏问孝,子曰“色难”,先儒以为“有深爱者必有和气,有和气者必有愉色,有愉色者必有婉容”。吾弟之事父兄多恭谨,然婉容愉色抑何少也!岂其无乐爱耶?盖无学问以化其刚,岸然之气,欲下之而不能下也。弟行勉之矣!                                                  

(选自《魏叔子文集》,有删改)

同类题5

阅读理解

    In this day and age taking a photograph is easier than ever. There are cameras built into our phones, computers, iPods…The way we share photos has also changed. There was a time when you'd print your photos and put them into photo albums, but because of the advance in technology, all in technology, all this has changed.

    Not only do we have what seems like an endless amount of space to store photos on our devices, but we also have the Internet, especially social media. Social networks such as Facebook allow us to post our pictures and albums to share friends and family.

    While you could argue this easy ability to store, share and enjoy photos is fantastic, it could also be said that photographs have lost some of their meaning. I have over 1000 pictures on my smart phone and several thousand stored on my computer. I love posting my pictures on Facebook. Sometimes, however, I try to ask myself, will I really want to look back at this picture of a coffee or a selfie taken in a bathroom by myself? Probably not.

    Even though I'm guilty about sometimes taking meaningless and boring pictures like this, a couple of years ago, I decided to find a way to make my photographs more meaningful. How did I do this? Disposable (一次性)cameras! When I go on a trip, I always try to take a disposable camera. With only 27 pictures you can take, you really think about the photograph straight away. And finally, it's so much fun to get the pictures developed and look through them again.

    I admit that I couldn't live without social media or taking photographs with my smart phone, but I do think taking photographs has become less meaningful. That's why I'll continue using disposable cameras. It's a great way to make your photographs more meaningful.