America's holiday shopping season started on Black Friday, the day after Thanksgiving.

{#blank#}1{#/blank#}Shoppers make the most money this time of year, about 20 percent to 30 percent of all revenue all year. About 136 million people shopped during the Thanksgiving Holiday weekend.

{#blank#}2{#/blank#}In an era of instant information, shoppers can use their mobile phones to find deals. Nearly 80 percent of this year's holiday shoppers, or about 183.8 million people, shopped on Cyber Monday.{#blank#}3{#/blank#}Online spending on Black Friday rose 15 percent to hit $2.7 billion this year. Cyber Monday spending increased 12 percent to $3 billion. NBC News reported that for many, shopping online was a more comfortable alternative than crowded malls.

      The shift to online shopping has had a big impact on solid shopping malls. Since 2010, more than 24 shopping malls have closed and anadditional 60 are struggling. Fortune says the weakest of the malls have closed. However, the business in malls is thriving again, it adds.  According to a survey, 94.2percent of malls were full with shops by the end of 2014.{#blank#}4{#/blank#}

      The average American consumer will spend about $805 on gifts. That's about $630.5 billion between November and December – an increase of 3.7percent from last year.

{#blank#}5{#/blank#}That goes toChina's Singles' Day, celebrated on November 11, which posted record sales of$14.3 billion in 2015.

A．More and morepeople shop online nowadays.

B．That is thehighest level in 27 years.

C．It is thebusiest shopping day of the year.

D．One-in-fiveAmericans used a tablet or smart-phone.

E．Thetraditional mall industry can hardly survive.

F．Cyber Mondayfalls on the Monday after Thanksgiving and Black Friday.

G．Nonetheless,Cyber Monday is not the biggest online shopping day in the world.

    Knowing the “right” thing to say and do as parents is not easy. But what if I told you there's ONE word you can add to your vocabulary that will help set your kids up for success for the rest of their lives? You'd let it flow effortlessly from your parenting lips, right?

    Well, that word is “practice”. It generates confidence and a “can do” attitude in kids when you use the word “practice” in place of the more commonly used word “try”. And here's why.

    “Try” means failure, or at the very least, doubt. From a very young age, we are always told to “try this”, “try that” and “try, try again”… “just try”. But “try” suggests the act of wondering what will happen instead of a clear intention of success.

    How many times have you heard someone say they tried something over and over, and it didn't work? Or that they will try to call you or come over and never show? Our subconscious(潜意识的) programming tells us that “try” is a way out for many. It's a word we use when we don't expect success or don't want to do something. We usually think, “Oh well, at least I tried.”

    The word “practice”, however, is different. Practice always makes you better. everyone who is good at something has practiced－doctors, musicians, athletes, students, speakers, singers and the list goes on and on. Did they try it the first time to see if they wanted to pursue it? Yes, but when it came to improving, they practiced. Even toddlers learning to walk are practicing. They have every intention of working successfully, and they keep at it until they do… and that in itself is a great lesson for us adults.

    If you want to get the most out of the study of a language, you must also read for pleasure: novels, plays, travel books, and so on. And in reading books of this kind the important thing is to get on with reading; to try to grasp what the writer is going to tell you in the book as a whole. This is impossible if you stop and think over the meaning of every single word which happens to be unfamiliar. You can not enjoy a story if you stop half a dozen times on every page in order to look up words in the dictionary. You may even prevent yourself from understanding the story as a whole by doing this.

    When you are reading books of this kind, therefore, you will usually have to rely mainly on the context to help you. If you meet an unfamiliar word, do not let it take too much of your attention from the main thread(主线) of the story. In all probability you will meet the same word again a few pages later on in a slightly different context, and each time you see it that your understanding of it will become more exact.

    A team of engineers at Harvard University in trying to create the first robotic fly. Designed to do what a fly does naturally, the tiny is the size of a fat housefly. Its mini wings allow it to stay in the air and perform controlled flight tasks.

    "The added difficulty with a project like this is that actually none of its components is off the shelf and so we have to develop them all on our own' said Robert Wood, a Harvard engineering professor.

    They engineered a series of systems to start and drive the robotic fly. "The seemingly simple system which just moves the wings has a number of interdependencies (相互依赖）on the individual components, each of which individually has to perform well, but then has to be matched well to everything it d connected to," said Wood.

    While this first robotic flyer is linked to a small, off-board power source, the goal is eventually to equip it with a built-in power source, so that it might someday perform data-gathering work at rescue sites, in farmers' fields or on the battlefield. "Basically it should be able to take off, land and fly around," he said.

    Wood says the design offers a new way to study flight mechanics and control at insect-scale. Yet, the power, sensing and computation technologies on board could have much broader applications." You can start thinking about using them to answer open scientific questions, you know, to study biology in ways that would be difficult with the animal, but using these robots instead" he said. "So there are a lot of technologies and open interesting scientific questions that are really what drives us on a day-to-day basis."

    Have you ever spent an afternoon in the backyard, maybe grilling or enjoying a basketball game, when suddenly you notice that everything goes quiet? There is an old phrase "calm before the storm", often used in a situation—a quiet period just before a great activity or excitement. According to our own experience, we know there is actually calm before the storm. But what causes this calm? And is it always calm before the storm? Let's hear what scientists have to say.

    A period of calm happens in a particular kind of storm, the simplest kind of storm—a single-cell thunderstorm. In this type of thunderstorm, there is usually only one main updraft, which is warm, damp air and drawn from places near the ground. Storms need warm and damp air as fuel, so they typically draw that air in from surrounding environment. Storms can draw in the air that fit their need from all directions—even from the direction in which the storm is traveling.

    As the warm, damp air is pulled into a storm system, it leaves a low-pressure vacuum (真空) coming after. The rising air meets the cold dry air that has already existed in the storm clouds, thus the temperature of the warm, damp air drops, and the water vapour (水蒸汽) in it changes into tiny drops that are a precondition of rain. These drops accumulate and build on larger particles like dust, until they grow large enough to form raindrops.

    This warm, damp air keeps moving upwards, but it becomes cooler and drier during its trip through cloud. When it reaches the top of the cloud, the air gets spit out (被挤出) at the top. This air is sent rolling out over the big thunderclouds. From there, the air goes down. Warm and dry air is relatively stable, and once it covers a region, that air, in turn, causes the calm before a storm.

    Most thunderstorms, though, don't start with calm. That's because most are actually groups of storms with complex wind patterns. There's so much air moving up and down storm groups that the calm before the storm never happens. Instead, before the storm,让 might be really windy!

    A headache is the feeling you get when your head hurts. Headaches can differ from very mild to incredibly powerful. They can last anywhere from 10 minutes to hours. Very bad headaches are called migraines. People who suffer from migraine headaches often need to take the day off from school or work and lie in bed all day.

    Why do people get headaches? There are many possible causes. People who drink too much caffeine (in coffee or soft drinks, for example) or alcohol can end up with headaches. This is because these kinds of drinks take water away from the body. If the brain doesn't have enough water, it gets smaller and pulls away from the head. This can be extremely painful. The best way to get rid of this kind of headache is just to drink lots of water.

    Tension headaches happen when the body's muscles are too tight. When people feel stress, it is common for the muscles near the head to become tense. Tension headaches might also be caused by not getting enough sleep. Some people suffer from tension headaches for only short times but for other people, these kinds of headaches are a chronic problem that happens again and again. A massage (按摩) might help to stop a tension headache. If that doesn't help, you might need to see a doctor.

    Headaches can also be caused by much bigger health problems. For example, a head or neck injury can cause them. Headaches can also be a warming sign of a heart attack.