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    bacteria. 细菌. 【查看更多】

     

    题目列表(包括答案和解析)

    阅读下面短文,用英语回答文后所给的5个问题。

    Bacteria(细菌) are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in micron. One micron is a thousandth of a millimeter; a pinhead is about a millimeter across. Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron across. Thus, if you magnified a rounded bacterium a thousand times, it would be just the size of a pinhead, while a grown-up human enlarged by the same amount would be over a mile tall.

    Even with an ordinary microscope(显微镜), you must look closely to see bacteria. Using a magnification of 100 times, one can hardly find bacteria. Nor can one make out anything of their structure(结构), of course. Only by using special colors, can one see that some bacteria have wavy-looking “hairs” called flagella. Others have only one flagellum. The flagella move round a central point, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can move along over surface by some little-understood “machinery”.

    From the bacterial point of view, the world is a very different place from what it is to humans. To a bacterium, water is as thick as molasses(糖浆) is to us. Bacteria are so small that they are affected by the movements of the chemical molecules(分子) around them. Bacteria under microscopes, even those with no flagella, often jump up and down in the water. This is because they knock with the water molecules and are pushed this way and that.

    47. What does the underlined word “magnified” mean?

    ________________________________________________________________

    48. What is the smallest according to the passage?

    ________________________________________________________________

    49. What is the relationship between a bacterium and its flagella is most nearly like?

    ________________________________________________________________

    50. Why does the writer compare water to molasses in the third paragraph?

    ________________________________________________________________

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    阅读下面短文,用英语回答文后所给的问题。

    　　Bacteria(细菌) are extremely small living things．While we measure our own sizes in inches or centimeters, bacterial size is measured in micron．One micron is a thousandth of a millimeter; a pinhead is about a millimeter across．Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron across．Thus, if you magnified a rounded bacterium a thousand times, it would be just the size of a pinhead, while a grown-up human enlarged by the same amount would be over a mile tall．

    　　Even with an ordinary microscope(显微镜), you must look closely to see bacteria．Using a magnification of 100 times, one can hardly find bacteria．Nor can one make out anything of their structure(结构), of course．Only by using special colors, can one see that some bacteria have wavy-looking “hairs” called flagella．Others have only one flagellum．The flagella move round a central point, pushing the bacteria through the water．Many bacteria lack flagella and cannot move about by their own power, while others can move along over surface by some little-understood “machinery”．

    　　From the bacterial point of view, the world is a very different place from what it is to humans．To a bacterium, water is as thick as molasses(糖浆) is to us．Bacteria are so small that they are affected by the movements of the chemical molecules(分子) around them．Bacteria under microscopes, even those with no flagella, often jump up and down in the water．This is because they knock with the water molecules and are pushed this way and that．

    1．What does the underlined word “magnified” mean?

    _______________________________

    2．What is the smallest according to the passage?

    _______________________________

    3．What is the relationship between a bacterium and its flagella is most nearly like?

    _______________________________

    4．Why does the writer compare water to molasses in the third paragraph?

    _______________________________

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    Translate the following sentences into English, using the words or phrases given．

    (用所给的单词或短语把下面的句子翻译成英语。)

    他们采用了一种新方法来杀灭牛奶里的细菌。(bacteria)(introduce)

    ________________________

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    阅读理解。
    阅读下面短文，并根据短文后面的要求答题。

         Experts are finding your standard first aid response may be the worst thing you can do in an emergency.
    Here's how to update your first aid kit.
         CUTS AND SCRAPES
          When the skin isn't broken, it's hard to beat iodine (碘酒) for killing bacteria(细菌). 3. _____________
    doctors use it to clean before surgery. But when there's a cut, full - strength iodine and rubbing alcohol can
    be harmful to skin cells, preventing healing. Putting iodine on cuts and wounds kills bacteria, but it won't clean
    the wound. The most effective way is washing the wound with water.
          BURNS
         If you spread some butter on the burn to ease the pain, it isn't a good idea. Butter was thought to cool the
    burn, but it can cause infection and create and environment for bacterial growth. Run the burn under cool
    water immediately to help remove the heat and put an end to the damaging process    . Wrap the burn with a
    bandage, and keep it clean and dry. If blisters (水泡) form, don't break them.
          POISONING
         When a child swallows anything poisonous, parents probably think they're well prepared if ipecac (催吐
    剂) is on hand. Wrong. Ipecac was thought to be a good way to treat a child who had swallowed a poisonous
    substance, but not any more because it doesn't always remove the toxic substance (有毒物质). That may
    cause dehydration (脱水) and prevent doctors from giving other treatments.
          EXCESS BLEEDING
          Everyone learns how to stop bleeding with a tourniquet (止血带). But studies show this method causes
    more harm than good. Tourniquets can increase the risk of tissue damage or even the loss of a limb. Apply
    direct pressure to the wound. Simply place a clean cloth on the wound and press firmly; don't remove the
    cloth, event if it gets black. If necessary, add more cloths. If that's not enough, you can further slow the
    blood flow by applying pressure to the main artery (动脉) of the upper arm or leg.

    1. What is the best title of the passage? (Please answer within 6 words.)
    ________________________________________________________________________________
    2. Which sentence in the passage can be replaced by the following one? However,
        by studying we know this method does more harm instead of doing more good.
    ________________________________________________________________________________
    3. Please fill in the blank with proper words or phrases to complete the sentence.
        (Please answer within 5 words.)
    _________________________________________________________________________________
    4. Translate the underlined sentence in the passage into Chinese.
    __________________________________________________________________________________

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    阅读下列短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。

    　　Most of us think that when we step under a shower we’re getting clean．We are, but we're also giving a home to lots of tiny little creatures we didn't even know about．

    　　A showerhead carries thousands of bacteria(细菌)called Mycobacterium．These can cause problems like coughs and tiredness, and a general feeling of poorliness(身体不舒服)．When you turn on the water, the bacteria go from the showerhead onto and into your body．

    　　This is a finding of Norman R．Pace and his team at the University of Colorado, in the US．The scientists investigated bacteria in all kinds of human environment, including showers．

    　　Pace's team looked at 45 showerheads in nine American cities．They discovered that 30 percent of them had large amounts of flying Mycobacterium．

    　　But Pace said that they pose few threats to the health．Only those with a frail(脆弱的)immune(免疫的)system might need to worry．

    　　He told the New York Times that the bactertia are not as unpleasant as might be thought．He said that having a shower is no more dangerous than anything else we do in the morning．

    　　But for those who feel sick about the idea of all those microorganisms(微生物), he had some advice．

    　　Let the water run for 30 seconds before getting into the shower．Why? The number of bacteria is smaller than when the water is just turned on．If that seems like a waste of water, he added that you could also change your showerhead every few months．

    　　But Pace had good news too．He has also been testing the air in US subways．Apart from iron particles(粒子), which are ground off the track by the wheels of trains, subway air is fresh．The reason is that a train's movement pumps fresh outdoor air into the tunnels(隧道)．

    　　Pace explained that he wanted to understand the natural microbial(微生物的)environments of public places．This kind of knowledge might help detect the microbes to be used in a bioterrorist(生物恐怖分子)attack．

    (1)

    According to the finding of Norman R．Pace, after taking a shower, we might ________．

    [　　]

    A．

    get much dirtier

    B．

    be covered by bacteria

    C．

    get a frail immune system

    D．

    catch a cough or feel tired

    (2)

    Pace's research into showers shows that ________．

    [　　]

    A．

    there is no reason to fear microorganism

    B．

    shower water contains much less bacteria after being left to run for 30 second

    C．

    having a shower in the morning is more dangerous than at other time

    D．

    of 45 showerheads surveyed in nine cities, 30 carried large amounts of Mycobacterium

    (3)

    According to the research of Pace's team, which of the following contributes to fresh air in US subways?

    [　　]

    A．

    Train wheels．

    B．

    Iron particles．

    C．

    The movement of the trains．

    D．

    Air conditioners on the trains．

    (4)

    The word “detect” in the last paragraph probably means “________”．

    [　　]

    A．

    to discover

    B．

    to protect

    C．

    to make

    D．

    to prevent

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