A brain can also simply be a smartperson,  If a person is called brainy,she is smart and intelligent. If a family has many children but one ofthem is super smart, you could say, "She's the brains in the family. "And if you are the brains behind something you are responsible for developing or organizing something. For example, Bill Gates is the brains behind Microsoft Brain trust is a group of experts who give advice. Word experts say the phrase "brain trust" became popularwhen Franklin D. Roosevelt first ran for president in 1932, Several professors gave him advice on social and political issues facingthe U.S.

    These professors were called his "braintrust." These ways we use the word"brain" all make sense. But other ways we use the word are not so easy to understand. Forexample, to understand the next brain expression, you first need to know theword “drain." As a verb to drain means to, remove something by letting it flow away. So abrain drain may sound like a disease where the brain flows out the ears. But, brain drain is when a country's most educated people leave their countries to live in another. The brains are, sort of, draining out of the country.

    However, if people are responsible for agreat idea, you could say they brainstormed it. Here, brainstorm is not an act of weather. It is a process of thinking creatively about a complex topic. Forexample, business leaders may use brainstorming to create new products, and government leaders may brainstorm to solve problems.

    If people are brainwashed, it does notmean their brains are nice and clean. To brainwash means to make someone accept new beliefs by using repeated pressure in a forceful or tricky way. Keep inmind that brainwash is never used in a positive way.

    Teachers' Day around the world is not celebrated on the same day.In some countries，Teachers' Day is celebrated on working days.However，in other countries，it is celebrated on holidays.

    Here we are giving you a list of countries that celebrate Teachers' Day on holidays.

China

    The Teachers' Day was proposed(提议)at National Central University in 1931.It was adopted(被采纳) by the central government of Republic of China in 1932.In 1939，the day was set on August 27，Confucius's birthday.People's Republic of China government called it off in 1951.It was reestablished in 1985，and the day was changed to September 10.Now more and more people are trying to celebrate the Teachers' Day back to Confucius's birthday.

India

    In India，Teachers' Day is celebrated on September 5，in honor of Dr Sarvepalli Radhakrishnan，the second President of India.Because his birthday was September 5th.At schools on this day，students in India celebrate this day to show their respect and love to their teachers.

Russia

    In Russia Teachers' Day is on October 5th.Before 1994，this day was set on the first Sunday of September.

USA

    In the United States，Teachers' Day is a holiday on the Tuesday of the first full week of May.

Thailand

    January 16 was adopted as Teachers' Day in the Thailand by a resolution(决议) of the government on November 21，1956.The first Teachers' Day was held in 1957.

Iran

    In Iran，Teachers' Day is celebrated on May 2nd every year.It is in honor of the famous Iranian professor Ayatollah Morteza Motahhari who died on May 2，1980.

    Although different countries celebrate Teachers' Day on different days，the activities people take to celebrate it just stay the same.

    In Western countries, bread is one of the most important foods. When they get up in the morning many people eat toast (烤面包). They spread butter and jam on their toast. People eat bread at other times of the day too. For example, at main meals, they often eat bread with soup.

    It's also very common to eat sandwiches. A sandwich is two pieces of bread with a filling inside - salad, cheese or fish. A hamburger is a kind of sandwich.

There are many different kinds of bread. Some are special to some countries. For example, the baguette (法国棍子面包) is a long, thin loaf that began in France.

    There is also white bread and whole-wheat (全麦面) bread. What's the difference? White bread is refined (精制的). It has things taken out of it to make it softer and easier to eat. The trouble is, white bread also has lots of goodness taken out. Although some people dislike the taste of whole-wheat bread, it is much healthier.

    Some kinds of bread have additives (添加剂). They are put into the bread for many reasons. Some additives are good for you - for example vitamin C. Others are there to make the bread last longer. Still others to make it taste better - but they do not necessarily make the bread healthier to eat!

    I became a magician by accident. When I was nine years old, I learned how to make a coin disappear. I'd read The Lord of the Rings and gone into the adult section of the library to be buried in fantasy literature but young enough to still hold out hope that you might find a book of real, actual magic in the library. The book I found taught basic techniques, and I tried to practice.

    At first the magic wasn't any good. It was just a trick—a bad trick. I spent hours each day running through the secret moves in front of the mirror. I dropped the coin over and over, a thousand times in a day, and after two weeks my mom got a carpet and placed it under the mirror to muffle (消音) the sound of the coin falling again and again.

    One day I made the coin disappear on the playground. We had been playing football and were standing in the field behind the school. A dozen people were watching. I showed the coin to everyone. Then it disappeared. The kids screamed. Everyone went crazy.

    A few years later, I staged an underwater escape in the river that flowed through the middle of the campus of the University of Iowa, where I went to school. I stood on a boat in the middle of the river wearing nothing but biking shorts. The sky was dead and gray, and the water was cold at the surface, and colder in the depths below.

    Technically, I succeeded. I jumped into the water, sank to the bottom, and escaped from the locks and the chains before swimming to the surface. But it didn't feel like a success.

    Measles (麻疹), which once killed 450 children each year and disabled even more, was nearly wiped out in the United States 14 years ago by the universal use of the MMR vaccine (疫苗). But the disease is making a comeback, caused by a growing anti-vaccine movement and misinformation that is spreading quickly. Already this year, 115 measles cases have been reported in the USA, compared with 189 for all of last year.

    The numbers might sound small, but they are the leading edge of a dangerous trend. When vaccination rates are very high, as they still are in the nation as a whole, everyone is protected. This is called "herd immunity", which protects the people who get hurt easily, including those who can't be vaccinated for medical reasons, babies too young to get vaccinated and people on whom the vaccine doesn't work.

    But herd immunity works only when nearly the whole herd joins in. When some refuse vaccination and seek a free ride, immunity breaks down and everyone is in even bigger danger. That's exactly what is happening in small neighborhoods around the country from Orange County, California, where 22 measles cases were reported this month, to Brooklyn, N.Y., where a 17-year-old caused an outbreak last year.

    The resistance to vaccine has continued for decades, and it is driven by a real but very small risk. Those who refuse to take that risk selfishly make others suffer.

    Making things worse are state laws that make it too easy to opt out (决定不参加) of what are supposed to be required vaccines for all children entering kindergarten. Seventeen states allow parents to get an exemption (豁免), sometimes just by signing a paper saying they personally object to a vaccine.

    Now, several states are moving to tighten laws by adding new regulations for opting out. But no one does enough to limit exemptions. Parents ought to be able to opt out only for limited medical or religious reasons. But personal opinions? Not good enough. Everyone enjoys the life-saving benefits vaccines provide, but they'll exist only as long as everyone shares in the risks.

    Facebook is an American online social media and social networking service. The Facebook website was launched on February 4, 2004, by Mark Zuckerberg, along with fellow Harvard College students and roommates.

    The founders had limited the website's membership to Harvard students at first; however, later they expanded it to various other universities, and eventually to high school students as well. Since 2006, anyone who claims to be at least 13 years old has been allowed to become a registered (注册了的) user of Facebook, though differences exist in the youngest age requirement, depending on local laws. Facebook has more than 2 billion monthly active users as of June 2017. As of April 2016, Facebook was the most popular social networking site in the world, based on the number of active user accounts.

    Facebook may be accessed by a large range of desktops, smartphones over the Internet and mobile networks. After registering to use the site, users can create a user profile (简介) showing their names and so on. Users can add other users as "friends", exchange messages, post photos and so on.

    Facebook makes most of its income from advertisements which appear on screen, marketing access for its customers to its users.