Who could have imagined that a treadmill (跑步机) on wheels would one day become a thing? The Lopifit is an unusual means of transportation that allows you to power an electric bicycle by walking on a treadmill. It's actually cooler than it sounds.

The Lopifit founder Bruin Bergmeester said it all started when he asked himself the question "How can I use a treadmill outdoors?" Then he spent the next few years figuring out a way to make it work He eventually came up with a functional design, added an electric engine, and the Lopifit was born. It's similar to an electric bicycle in that the motor only engages when the rider puts power in as well. Only while typical electric bikes are given pedal assist, the Lopifit senses when you walk on the treadmill and use the motor to turn a drive chain under the treadmill, helping you reach a top speed of 17 miles per hour.

To use the Lopifit, simply turn on the battery and use your foot to slide the treadmill backwards and then start the motor. Then get on and enjoy the ride! H you need speed, just walk on the treadmill, and if you want to coast, all you have to do is stay still and admire the view. To stop, you have two hand breaks. The right hand break stops the electric bicycle, while the left one stops the treadmill itself. It sounds and actually looks simple enough to use, but most of those who have tried it say that it takes some time to get used to it.

    The Lopifit first hit the streets in 2014 and, unsurprisingly, became an instant hit. That was actually quite challenging for the company, because it started getting calls for orders, but it was nowhere near ready for mass production. The unique treadmill bicycle became available this year, and the Lopifit is struggling to keep up with demand, despite the high price, $2,115.

    The single, decisive factor that made it possible for mankind to settle in lasting communities（社区，聚居地）was agriculture. After farming was developed in the Middle East in about 6500 BC, people living in family units did not have to be on the move continually searching for food or hunting their animals. Once people could control the production of food and be assured of a reliable supply of it, their lives changed completely.

    Farming was a revolutionary discovery. It not only made settlements possible and later the building of cities but it also made available a reliable food supply. With more food available, more people could be fed. Population therefore increased. The growing number of people available for more kinds of work led to the development of new social formations. With more and more food, a community could support a variety of workers who were not farmers.

Farming in the world over has always relied upon a dependable water supply. For the earliest societies this meant rivers and streams or regular rainfall. The first great civilizations grew up along rivers. Later communities were able to develop by taking advantage of the rainy seasons.

    All of the ancient civilizations probably developed in much the same way, in spite of a few differences. As villages grew, the production of more numerous goods became possible. Cloth could be woven from wool. Houses made of wood, brick, and stone could be put up.

    The science of mathematics was an early outcome of agriculture. People studied the movements of the moon, the sun, and the planets to work out seasons, By doing so they created the first calendars（日历）. With a calendar it was possible to find out the arrival of each growing season. Measurement of land areas was necessary if field was to be divided accurately. Measurement of amounts, for example, of seeds or grains was also a factor in farming and housekeeping. Later measures of value as money exchange became common.

    All of the major ancient civilizations in Mesopotamia, Egypt, the Indus Valley, and China appeared in the 4th millennium（千年）BC. Historians still argue over which one came into being first. It may well have been the Middle East. This place reaches out from the Nile River in Egypt northward along the coast of former Palestine, then eastward into Asia to include Mesopotamia. In this area people settled along the riverbanks and practiced field agriculture. This kind of farming depended on the reproduction of seed, normally from grain crops.

    With child behavior, there is almost much more than it meets the eye. Because it occurs at so many different levels, child behavior that seems simple at one level can often be much more complex and meaningful at another.

    For instance, a little child's pattern of getting into cupboards, drawers and closed rooms, even after being told not to, is easily considered as bad behavior. When viewed at that level, the pattern is unacceptable and could lead to punishment. But it can be viewed at a more complex and meaningful level, namely child exploration. If a child regularly experiences an angry parent who seems determined to prevent any exploratory activities, the child will decide to continue to achieve future discoveries. When parents view this behavior as born out of natural curiosity rather than simple opposition, they are more likely to accept and appropriately monitor it. Although it may lead to warning responses to ensure the child's safety, it is less likely to lead to punishment.

    There are countless other examples. Holding a goldfish outside its bowl is foolish at one level but also can be seen as a young child's attempt to express physical affection for a pet. Spending time with friends rather than family is selfish at one level but also indicates a teen's need for independence.

    The point here is that child behavior is often exhibited in simple forms that can appear to be oppositional, selfish or generally unacceptable if viewed only at that basic level. However, when viewed at a more meaningful level, the same apparently simple behavior can be seen as something larger and potentially more adaptive. This doesn't mean the behavior should be ignored, especially if it is inappropriate. But looking at the bigger picture of a child's behavior, adults might gain a fuller understanding of what they're dealing with, which can create more flexibility in how they respond.

    You probably know that frogs hop (双足跳). But did you know that there's a small frog in the Pacific Northwest that belly flops (肚子先着水)? It's called a tailed frog.

    Dr. Rick Eisner, who has been studying tailed frogs for the past few years, says, "I've looked at thousands of jumps and have never seen them land on their feet like other frogs." Most of the time, tailed frogs land on their stomachs and then bring their back legs in to prepare for another jump.

    Eisner first noticed these frogs because of the way they swim. Other frogs kick both of their back legs at the same time. But when a tailed frog swims, it pushes first with one leg and then the other.

    To try to find out why tailed frogs bellyflop, Eisner and other scientists collected and filmed different kinds of frogs. They found that all of the frogs start their jumps the same way: They hold out their legs. The change comes in the landing. Tailed frogs can't move their back legs as quickly as other frogs do. Maybe they don't need to. Tailed frogs live around water and quickly jump into the water to escape danger.

    Early frogs developed around watery areas and could jump quickly into the water to escape danger. Scientists think those frogs blended in with (与…融合在一起) the green plants on the side of the rocky rivers, just like today's tailed frogs. "I would guess that other animals would have problems detecting them," explains Eisner. When other animals find those early frogs, the frogs could jump into the river. They didn't need to continue hopping.

    Tailed frogs and other kinds of frogs went their own ways about 200 million years ago. Tailed frogs stayed by rivers. Other kinds of frogs moved to places where new hopping skills allowed them to survive.

    Samuel Morse was born in Massachusetts USA. He started off his career as an inventor after being a painter and sculptor (雕塑家). He even earned a gold medal from the famous Adelphi Society of Arts for his first effort in sculpture, the "Dying Hercules". He became the first president of the National Academy of Design, and was made Professor of the Arts of Design in the University of the City of New York.

    Yet, this painter turned to inventing to make his fortune during a sea voyage. On this journey, Samuel Morse heard about many attempts to create usable telegraphs. He was fascinated by this problem and began to study books on physics for two years to gain more scientific knowledge. He realized that pulses (脉冲) of electrical current could carry information over wires.

    Thus the world's first working model of a telegraph was born. His signaling device was quite simple. It consisted of a transmitter (containing a battery and a key), a small buzzer (蜂鸣器) as a receiver and a pair of wires connecting the two. Samuel Morse improved it by adding a switch and a second buzzer to allow transmission (传播) in the opposite direction as well.

    On May 24, 1844 Samuel Morse sent the first electronic message between Baltimore and Washington, "Look what God has enabled us to build, and benefit by."

    Seventeen years later, the two coasts of the United States were linked by telegraph. The telegraph continued to enjoy the position of being the fastest and most reliable means of communication for almost 140 years since its invention.

Bathed in two cultures from childhood, moving around the world and experiencing different cultures has always been my thing. When I was in high school, I heard about students in my class wanting to take the SAT test and study abroad in the USA. {#blank#}1{#/blank#}. Actually, what I wanted to experience most was the European lifestyle and cultural mix.

 I used to travel a lot around Europe with my parents as a little kid, and also not forgetting that the French Language is one of my mother tongues, France seemed therefore like a top choice for me. French universities have a good reputation and the French capital is internationally well known for its cultural history. {#blank#}2{#/blank#}. My university was one of those small cities and I also got the chance to obtain a scholarship which made it easier for me to start my studies.

 {#blank#}3{#/blank#}. Opportunities are offered to develop our network and explore the business world. The university participated as a partner in international networking courses leading to a European Master's degree, a double degree, or training abroad.

    {#blank#}4{#/blank#}. So, if you are an international student who came to France for studies, you can take the chance to explore another country for a term and study in English. I remember wanting to take this opportunity in my first year of my college life and try the program which back then offered students the chance to go on an exchange with Linnaeus University in Sweden. {#blank#}5{#/blank#}.

A.I applied and was lucky to get accepted

B.But I was not that attracted to studying there

C.You can find a lot of student-friendly cities as well

D.Besides, all these universities have their own unique advantages

E.The university I chose was small but used to invite business chiefs and directors

F.Because there are many universities with good reputation which attracts students

G.Plus, all French universities work with several countries to offer an exchange program