The article does not mention whether the scientists' experiments with dogs have ______.A．b

The article does not mention whether the scientists' experiments with dogs have ______.

A．benefited animals other than dogs

B．served man

C．helped other dogs

D．contributed to medical knowledge

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发布时间：2022-12-03

更多“The article does not mention whether the scientists' experiments with dogs have ______.A．b”相关的问题

第1题

The timing of flu season is a little hard to predict. Part of what makes it unpredictable

is that scientists still don t understand exactly why we have one at all. There have been lots of theories: One theory is that people spend more time indoors, with the windows closed, breathing each other s air. Other scientists have argued that cold of winter weakens our immune systems. A third theory is that the flu virus lives in the cold, dry air, but suffers in the warm, humid air. For a while, scientists had a hard time testing these theories: they needed to run experiments, but researchers aren t allowed to infect humans with illnesses, and most lab animals arent affected by the flu the same way people are. In 2007, a medical researcher named Peter Palese found an 80-year-old journal article that reported that guinea pigs (豚鼠)get infected and pass on the flu just like humans. Palese decided to test Theory 3. The research team led by Palese ran several experiments and in each experiment, they injected half the guinea pigs with influenza A (the common flu), and put them in a box next to a box of uninfected animals. At a temperature of 41 degrees, all four of the exposed guinea pigs caught the flu, but when Palese repeated the experiment at 68 degrees, only one of the animals was infected. And when he ran the test at 86 degrees, none of the exposed animals got sick. The researchers also ran experiments where they varied the humidity in the room but kept the temperature constant: the drier the air, they found, the more animals got sick. Palese s study showed that the influenza virus does spread more effectively in cold, dry air.

What does Paragraph 3 mainly discuss？

A．The direction for future research.

B．The necessity of running more tests.

C．The difficulty of testing the theories.

D．The cost of animal experiments.

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第2题

Exercise, everyone advises! But immediately, when you try, you run into trouble. There is

so much contradictory, sometimes incorrect advice about exercising that you become confused. Test yourself on the following true false quiz. It will tell you what you need to know.

1. To lose weight you should always "work up a good sweat" when exercising.

False. Sweating only lowers body temperature to prevent overheating; it does not help you reduce weight. You may weigh less immediately after a workout, but this is due to water loss. Once you replace the liquid, you replace the weight.

2. You burn more calories jogging one mile than walking the same distance.

False. You use the same amount of energy whether you walk or jog the mile, since in both cases you are moving the same weight the same distance. The speed doesn't matter. Of course, if you jog rather than walk for 30 minutes, you'll cover more distance, and therefore burn more calories.

3. If your breathing doesn’t return to normal within minutes after you finish exercising, you' ve exercised too much.

True. Five minutes or so after exercising, your breathing should be normal, your heart shouldn't be pounding, and you shouldn’t be exhausted. Beneficial exercise is not too difficult, unpleasant, and exhausting; it is enjoyable and refreshing.

4. Walking is one of the best exercises.

True.. Walking helps circulation of blood throughout the body, and thus has a direct effect on your overall feeling of health.

This article explains ______.

A．the difficulties of exercising

B．why exercising is good for your health

C．important information to know about exercising

D．why people have some wrong ideas about exercising

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第3题

The buyer suggested that the packing of this article （) improved.

A.be

B.was to be