If someone asked you to quantify (衡量) the time you spend online, how would you answer? If you're like one-fifth of Americans, you'd likely say “almost constantly.” New research shows that 21 percent of Americans report that they're online more or less constantly.

    Andrew Perrin, a research assistant at Pew, did a survey about Internet use. During the survey, adults were asked how much they go online. 13 percent said they don't go online and 13 percent said they go online several times a week or less. Only 10 percent said they go online once a day and much larger quantities said they go online several times a day (42 percent) or “almost constantly” (21 percent).

    Interestingly, there wasn't a gender split (性别分化) when it came to near constant Internet use. Age seems to be the great divider: Only six percent of people over 65 said they were online that much. Those who reported that they were online all the time included 12 percent of 50- to 64-year-olds, 28 percent of 30- to 49-year-olds and 36 percent of 18- to 29-year-olds.

    Don't suppose that teenagers are online more than adults, however. In another survey, Pew found that while they did have a slight edge on adults in general when it came to “almost constant” Internet use, 24 percent said they were online pretty much all the time. They still fell greatly behind the 36 percent of adults between 18 and 29 years of age who were always online.

    Given that the United Nations considers unrestricted (无限制的) Internet access (接入) to be a human right, the number of Americans who report being online “almost constantly” could rise along with availability and affordability. But it remains to be seen whether being online all the time is actually something to long for, or how constant connectivity will affect American culture in the long term.

    Pizza is a pretty universal treat, but where did it start? Here are three things you probably didn't know about pizza.

    1: Pizza's Origins Are Half-Baked.

    The Neapolitans（那不勒斯人）in Italy are proud of saying they invented pizza, but it's probably more accurate to say, they perfected it. The idea of putting toppings on a flatbread and baking it started in the 6th century B. C. But the people of Naples were the first to put tomato on a flatbread in the 16th century. From its start, pizza was a food of the poor, as it was cheap, filling and easy to eat on the run. In Italian, the word “pizza” refers to anything that is made and then pressed flat.

    2: Pizza Margherita Is Not Exactly a Symbol of Italy.

It was said some day in 1889, a local baker named Raffaele Esposito created three pizzas for Queen Margherita when she was on a tour of Italy. The queen loved the version that had tomato, basil and mozzarella cheese— and just happened to match the colors of the Italian flag. So Esposito named the pizza after her.

    But Pizza historian Scott Wiener points out that Italy was unified in name only in 1889 so it was unlikely any Neapolitan baker would want to celebrate “the Northern conquerors.” Further, the letter of gratitude for the pizza from the royal household that Pizzeria Brandi displays appears to be a fake（赝品）and may just have been a marketing plan.

    3: Hawaliian Pizza Invented by a Canadian.

    Sam Panopoulos, from Greece originally moved to Canada at the age of 20. In 1962, he decided to put some ham and pineapple on a pizza at one of his restaurants in Ontario.

    “We just put it on for fun to see how it was going to taste,” he told the BBC in 2017. Panopoulos named it the Hawaiian pizza after the brand of canned pineapple he used. The mix of sweet and savory toppings caught on with a certain part of the pizza-loving public. The inventor died in 2017.

    Memory, they say, is a matter of practice and exercise. If you have the wish and really make a conscious effort, then you can quite easily improve your ability to remember things. But even if you are successful, there are times when your memory seems to play tricks on you.

    Sometimes you remember things that really did not happen. One morning last week, for example, I got up and found that I had left the front door unlocked all night, yet I clearly remember locking it carefully the night before.

    Memory "tricks" work the other way as well. Once in a while, you remember not doing something, and then find out that you did. One day last month, for example, I was sitting in a barber shop waiting for my turn to get a haircut, and suddenly I realized that I had got a haircut two days before at the barber shop across the street from my office.

    We always seem to find something funny and amusing in incidents caused by people's forgetfulness or absent -mindedness. Stories about absent -minded professors have been told for years, and we never get tired of hearing new ones. Unfortunately, however, absent -mindedness is not always funny. There are times when "tricks" of our memory can cause us great trouble.

    Professor Smith recently persuaded 35 people, 23 of them women, to keep a diary of all their absent-minded actions for two weeks. When he came to analyze their embarrassing lapses(差错)in a scientific report, he was surprised to find that nearly all of them fell into a few groupings. Nor did the lapses appear to be entirely random(随机的).

    One of the women, for instance, on leaving her house for work one morning threw her dog her earrings and tried to fix a dog biscuit on her ear. "The explanation for this is that the brain is like a computer," explains the professor. "People program themselves to do certain activities regularly. It was the woman's custom every morning to throw her dog two biscuits and then put on her earrings. But somehow the action got reversed(颠倒的)in the program," About one in twenty of the incidents the volunteers reported were these "program assembly failures".

    Altogether the volunteers logged 433 unintentional actions that they found themselves doing—an average of twelve each. There appear to be peak periods in the day when we are at our zaniest (荒谬可笑的). These are two hours sometime between eight a.m. and noon, between four and six p.m. with a smaller peak between eight and ten p.m. "Among men the peak seems to be when a changeover in brain 'programs' occurs, as for instance between going to and from work." Women on average reported slightly more lapses—12.5 compared with 10.9 for men—maybe because they were more reliable reporters.

    An astonishing finding of the research is that the absent-minded activity is a risk of doing things in which we are skilled. Normally, you would expect that skill reduces the number of errors we make. But trying to avoid silly slips by concentrating more could make things a lot worse—even dangerous.

There has been tremendous concern recently over misinformation on social media. This concern is quite justifiable, as the consequences of believing false information are greatly affecting the individual and collective health.

Many people tend to fall for misinformation they encounter online. There is one influential explanation for this phenomenon. As the thinking goes, someone, who possesses very limited skills in finding and consuming digital content, creating digital content, and communicating it, is likely to have difficulty recognizing false information and thus is more vulnerable to believing false information. As a result, these less digitally literate people may play a significant part in the spread of misinformation.

This argument sounds perfectly plausible. Yet very little research has actually investigated the link between digital literacy and the vulnerability to believing false information. There's even less understanding of the potential link between digital literacy and what people share on social media. A group of MIT researchers explored these potential associations by surveying 1,341 Americans.

In the experiment, the researchers first showed the participants two dozen news headlines about politics, half of which were accurate, and half of which were false. In the second phase, they included a series of tests: having the participants report their familiarity with various Internet-related terms and answer questions about how social media platforms decide what to show in their newsfeeds. At last, the participants were required to assess the accuracy of a set of headlines and point out their likelihood of sharing each headline on social media.

The researchers found "clear evidence" that digital literacy was a strong predictor of accuracy discernment (识别能力). However, the results were "strikingly different" regarding sharing discernment. Digitally literate subjects were just as likely to share inaccurate information. Most surprisingly, even people with high digital literacy were not immune from clicking "share" for false news.

This sounds odd. Although most people don't want to spread misinformation, social media is distracting: people are scrolling quickly, and their attention is drawn to social validation (社会认知度), such as how many likes their posts will get. So make sure a certain post is accurate before you click the "share" button.

First aid is a simple medical treatment that gives a person who suddenly becomes ill before a doctor can be found. It's believed that four hundred and eighty seconds after an accident can make a difference between life and death. {#blank#}1{#/blank#} Here are some different situations where you can learn, how to give first aid.

Burns

{#blank#}2{#/blank#} It's the best to place burns under softly running water for about 10 minutes. Remember that don't use ice!

Nosebleed

Ask the person to lean forward and pinch the nose for five to six minutes. {#blank#}3{#/blank#} If so, the blood may run into the mouth.

Dog Bites

Wash the bite with plenty of water at a comfortable temperature. {#blank#}4{#/blank#} Then, go to see the doctor at once and follow their suggestions carefully.

Chocking (窒息)

Stand behind the chocking person put your arms around his body and lean him or her forward slowly. Press his or her stomach. {#blank#}5{#/blank#} You can also hit his back with your hand.