题目内容

【题目】— Another Friday! Everyone prefers weekends to weekdays!

— Is that so? I always have _______ weekend as a new mother.

A.a busierB.the easiestC.an easierD.the busiest

【答案】A

【解析】

句意:——又一个星期五!每个人都喜欢周末而不是工作日! ——是这样吗?作为一个新妈妈,我的周末总是很忙。

考查形容词的比较级。busy:繁忙的;easy:容易的。根据“Everyone prefers weekends to weekdays!”每个人都喜欢周末而不是工作日!可知,人们喜欢周末的原因是因为周末不忙,因此排除B/C;根据“Is that so?”以及“as a new mother.”可知,作为一个新妈妈,我的周末总是很忙。应该用形容词的比较级。故选A

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【题目】Bacterial Quorum Sensing

Bacteria(细菌)play an important role in our lives. They can keep us alive as well as make us sick. It wasn’t until fairly recently that we learned bacteria can communicate with one another.

In the 1960s, researchers found that a kind of bacteria called Vibrio fischeri(费氏弧菌) produced no light when they were alone, but that they exhibited great amount of light as the bacterial population grew to a certain number. How did this happen? How can Vibrio fischeri tell the difference between times when they’re alone and times when they’re in a community, and then all do something together?

Researchers found they talk to each other with a chemical language—signal molecules(信号分子). Vibrio fischeri makes signal molecules, and it also has a receptor on its surface that fits like a lock and key with a signal molecule. As the bacteria increase, more and more signal molecules are sent into the environment. When signal molecules increase to a certain amount, they lock down into those receptors and information comes into the bacteria, which tells them how many neighbors there are. As soon as they realize the population has hit the certain number, all of the bacteria behave as a group, making light together. In the past ten years, researchers have found all bacteria have systems like this: they make and recognize chemical words, determine(判断)the size of the community, and carry out tasks that would be unsuccessful if a single one were to act alone. This process is called quorum sensing.

Most of the time, bacteria live with thousands of other species (种类)of bacteria. There has to be a language of interspecies communication. In fact, bacteria have another kind of signal molecule, which is the common language used by all species. Moreover, this kind of molecule has its own receptor. In this way, bacteria are able to count different populations, and then they decide what task to carry out depending on which species has the greatest population.

Knowing how bacteria communicate could influence how we fight disease. What if bacteria can’t talk or hear? They won’t recognize when there are enough bacteria and when to exhibit the group behavior to make us sick. Researchers are developing a method—to make molecules that look like the real ones and then they lock into the receptors to jam recognition of the real situation.

On the other hand, researchers also improve the conversation of the beneficial bacteria, so they can do things that we want them to do better than they would do on their own.

1According to the passage, what can we learn about quorum sensing?

A.Quorum sensing may happen when there is only one Vibrio fischeri.

B.Signal molecules are kept away from receptors during quorum sensing.

C.Most bacteria have similar systems to make light during quorum sensing.

D.Bacteria carry out a group task when their population hit a certain number.

2What can we learn from the passage?

A.The more species there are, the more group actions bacteria will take.

B.In different environments, bacteria have different interspecies languages.

C.Beneficial bacteria communicate better by themselves than harmful ones.

D.To fight disease, researchers try to turn off the communication between harmful bacteria.

3The passage is mainly about ________.

A.why bacterial population growsB.how bacteria communicate with each other

C.which bacteria help fight diseaseD.what scientists do to find quorum sensing

【题目】 Infrared thermometers(红外温度计), or temperature guns, have been widely used to detect(检测)the early symptoms of COVID-19. They allow us to measure(测量)temperatures quickly. How do these thermometers work?

They determine temperature by measuring the energy coming from your skin (皮肤). Everything in nature has molecules (分子) inside of it that are always moving around. This include our skin. The higher the temperature is, the faster the molecules move. The molecules give off infrared light while moving.

This kind of light can be focused or absorbed(吸收). The thermometers use a lens(镜头)to focus infrared light from the skin onto a detector called a thermopile(热电堆). The thermopile absorbs the infrared radiation and turns it into heat. The electronic sensors inside the thermometers can measure the heat and read the temperature of the skin after making some calculations (计算).

However, you might sometimes find that the results aren’t always accurate (准确的). It depend on how these devices are used. For example, how far away they are held from the body, how steadily they are held and for how long. Factors such as make-up and sweat will also affect the results.

1Temperature guns, have been widely used to detect (检测)the early symptoms of____________.

A.COVID-17.B.COVID-18.C.COVID-19.D.COVID-20.

2They determine temperature by measuring the energy coming from your____________.

A.skinB.headC.faceD.foot

3The electronic sensors inside the thermometers can measure the heat and read the____________ of the skin.

A.colorB.temperatureC.lightD.structure

4Which one of the following might not affect the accurate results?

A.The thermometers is too far from the body.

B.The thermometers is held for very long.

C.Make-up and sweat.

D.The thermometer is held steadily at the right time.

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