Before going outside in the morning, many of us check a window thermometer (温度计) for the temperature. This helps us decide what to wear.

    {#blank#}1{#/blank#}. We want our food to be a certain coldness in the refrigerator. We want it a certain hotness in the oven. If we don't feel well, we use a thermometer to see if we have a fever. We keep our rooms a certain warmth in the winter and a certain coolness in the summer.

    Not all the thermometers use the same system to measure temperature. We use a system called the Fahrenheit scale. But most other countries use the Centigrade scale. Both systems use the freezing and boiling points of water as their guide. {#blank#}2{#/blank#}.

    The most common kind of thermometer is made with mercury inside a clear glass tube. As mercury (or any other liquid) becomes hot, it expands. As it gets colder, it contracts. That is why on hot days the mercury line is high in the glass tube. {#blank#}3{#/blank#}.

    First, take a clear glass juice bottle that has a cap; fill the bottle with colored water. Tap a hole in the center of the cap using a hammer and thick nail. Put the cap on the jar. Then stick a plastic straw through the nail hole.

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    Finally, place a white card on the outside of the bottle and behind the straw. Now you can see the water lever easily.

    {#blank#}5{#/blank#}. As the temperature goes down, the water will contract, and the lever in the straw will come down. Perhaps you will want to keep a record of the water lever in the straw each morning for a week.

    The English language has a lot of words which can be used in many different ways and in many different expressions.

    One such example is the word matter. In fact, matter can mean just about anything. It could be one of the most useful words in the English language.

    Let's get to the heart of the matter —a matter of principle(原则).

    If someone says that you owe(欠) him $50, but you don't, a friend might say, “Well, you could pay him the $50. It's not that much money. Then you won't have to hear him say it anymore. But if you do not owe him the money, do not pay him the money. It's a matter of principle.

    There is another way to use the word matter. But be careful with your choice of words.

    If you ask someone, “What's the matter?”, it shows you are worried about the other person. But saying, “What's the matter with you?” has a completely different meaning. And it usually sounds rude (粗鲁的). In fact, when you say, “What's the matter with you?” you are suggesting that the person did something wrong or stupid.

    Another expression that could sound rude is to say, “It doesn't matter to me.” Here, it depends on the context, and how you say it.

    Let's say you tell someone that a friend just got a big raise at work. That person answers with, “It doesn't matter to me.” Here, it means he or she does not care. And it sounds rude.

    But saying, “Oh, you pick where we eat dinner. It doesn't matter to me.” does not sound rude. In this situation, “it doesn't matter” shows you are easy-going(随和的).

    No matter how you look at it and what you say, matter is a very useful word. And it's only a matter of time before you will become an expert on the use of matter.

    Could the device, smartphone or PC，which you're using affect the moral decisions you make when using it? To test it, researchers presented multiple dilemmas to a sample set of 1,010 people. The participants were assigned a device at random.

    One case of the questions participants were asked is the classic “trolley (有轨电车) problem”: A runaway trolley is headed towards five people tied up on a set of train tracks. You can do nothing, resulting in the deaths of five people, or push a man off a bridge, which will stop the trolley. The practical response is to kill one man to save five lives, which 33.5 percent of smartphone users chose, compared to 22.3 percent of PC users.

    “What we found in our study is that when people used a smartphone to view classic moral problems, they were more likely to make more unemotional, reasonable decisions when presented with a highly emotional dilemma, ”Dr Albert Barque-Duran, the lead author of the study, told City, University of London. “This could be due to the increased time pressure often present with smartphones and also the increased psychological distance which can occur when we use such devices compared to PCs.”

    As for why the researchers started this study, Dr Barque-Duran noted, “Due to the fact that our social lives, work and even shopping take place online, it is important to think about how the contexts where we typically face moral decisions and are asked to engage in moral behavior have changed, and the impact this could have on the hundreds of millions of people who use such devices daily.” It's clear that we need more research on how our devices affect our moral decision making because we're using screens at an ever-increasing rate.

    He wrote that the “human mind is capable of excitement without the application of unpleasant and violent stimulants (刺激物)”. And it appears that simply reading these words by William K Wordsworth proves his point.

    Researchers at the University of Liverpool found the writing of Shakespeare and Wordsworth and the like had a beneficial effect on the mind, making it active and excited by catching the reader's attention and leading to moments of self-reflection.

    Using scanners, they monitored the brain activity of volunteers as they read pieces of classical English literature both in their original form and in a modem translation. And according to the Sunday Telegraph, the experiment showed the more challenging writing and poetry set off far more electrical activity in the brain than the simple readings.

    The research also found poetry, in particular, increased activity in the right brain, an area concerned with “autobiographical memory”, which helped the readers to reflect on their own experiences in light of what they had read. The academics said this meant the classics were more useful than self-help books.

    The brain responses of 30 volunteers were monitored in the first part of the research as they read Shakespeare in its original and modern form. In one example, volunteers read a line from King Lear, “A father and a gracious aged man: him have you madded”, before reading the simpler, “A father and a gracious aged man: him you have enraged”. Shakespeare's use of the adjective “mad” as a verb caused a higher level of brain activity than the straightforward version.

    The next part of the research is looking at the extent to which poetry can affect psychology and provide benefit. Volunteers' brains were scanned while reading four lines by Wordsworth, and four “translated” lines were also provided. The result showed that the first version caused a greater degree of brain activity.

    “Poetry is not just a matter of style. It is a matter of deep versions of experience that add the emotional and biographical to the cognitive (认知的),” said Professor Davis, leader of the researchers.

    Winter is the perfect time to see Washington in a different light. The crowds have thinned, and those humid 95-degree days are long gone. And the National Zoo is a different experience because of 500,000 bulbs that illuminate the annual Zoo-lights celebration.

    Eco-friendly twinkly lights will decorate zoo walkways, trees and buildings. Sculptures featuring popular zoo residents, including elephants and giant pandas, light up in time to music.

    If walking and watching isn't enough excitement, head to Lion & Tiger Hill, home to a 150-foot-long snow-less tubing run. Rides on the trackless train and the carousel also will be available.

    Don't forget to visit a few of the zoo's real animals. The Kids' Farm, Reptile Discovery Center, Small Mammal House, Think Tank (orangutans) and Great Cats exhibit will be open in the evening. There's no guarantee, however, that the animals will be as lively as the humans in attendance.

    When: Friday to January 1 (except December 24-25), 5 to 9 p.m.

    Where: 3001 Connecticut Ave. NW, Washington, D.C.

    How much: Admission is free; limited parking is $22. Charges for tubing, train rides and carousel rides.

    For more information: A parent can visit nationalzoo.si.edu/events/zoolights.

    More ZooLights celebrations: For those outside of the D.C. area, here are some links to other zoos with similar events (not all are free):

    Columbus Zoo, Ohio: Through January 1.

    Detroit Zoo, Michigan: Through December 31.

    Denver Zoo, Colorado: December 2-January 1.

    Houston Zoo, Texas: Through January 15.

    Moving flight times from night to day could reduce air travel's contributions to global warming, a new study suggests. Scheduling more (lay time flights may reduce the influence of contrails ——the visible lines of white steam that many planes leave behind them in the sky.

    The role of contrails in climate change is still being studied, but some scientists believe they contribute to the greenhouse effect by trapping heat in the atmosphere.

    Nicola Stuber, first author of the study, suggests that contrails' overall impact on climate change is almost as big as that of aircraft^? s carbon dioxide emissions (排放)over a hundred-year period. Aircraft are believed to be responsible for 2-3% of human carbon dioxide emissions. Like other high, thin clouds, contrails reflect sunlight back into space and cool the planet. However, they also trap energy in the atmosphere and increase the warming effect.

    Stuber and other scientists believe that the effect of the contrails is big. "On average, the green-house effect controls the effects of contrails, said Stuber, a meteorologist at England's University of Reading." The warming effect is far greater for contrails left by night flights," Stuber added. "The cooling effect only happens (luring the day when the sun is up. During the night the greenhouse warming is no longer balanced and that is why the contribution of night-flight is so large."

    Most commercial airline traffic occurs during daylight hours. For example, only one in four United Kingdom flights is a night flight, but those flights create some 60% of the warming created by contrails, the study reports.