B

    People often think of the North Pole(北极) and the South Pole as similar frozen(冰冻的) wastelands. They are both places with very cold temperatures and few people live there. However, the North and South Poles are not much alike as people may imagine.

    The North Pole has no land, only thick ice. Temperatures seldom go above 32°F, at which water turns into ice. Most of the time, it stays below zero. In winter temperatures are usually as low as -30°F.

    Although conditions were very poor, people tried for many centuries to reach the North Pole. About 100 years ago, two men, Robert Peary and Mathew Henson, were able to get to this environment full of troubles and difficulties. They reached the North Pole on March 8th, 1909. It was really a hard trip for them.

    There are few things more dangerous than crossing the Arctic(北极圈) on foot. People who stayed there may face many problems: very cold temperatures, sudden storms, and even hunger. Most of the area is uninhabited. Few people can live in such a difficult place.

    People might think that with such low temperatures for most of the year, the ice would be thick and hard. However, this is not true in the Arctic. The movement of the ocean water under the ice may often cause many different changes on the surface. Sometimes the ice breaks into two opening lanes of water(水道) called “leads”. Anyone who falls into a lead can be frozen to death in a few minutes.

C

    Different weather makes people feel different.It has an effect on health，intelligence(智力) and feelings.

    In August，it is very hot and wet in the southern part of the United States.People there have heart trouble and other kinds of health problems during this month.In the Northeast and the Middle West，it is very hot at some times and very cold at other times.People in these states have more heart trouble after the weather changes in February or March.

    The weather can also influence intelligence.For example，in a 1983 report by scientists, the IQ(智商) of a group of students was very high when a very strong wind came，but after the strong wind，their IQ was 10% lower.The wind can help people have higher intelligence.Very hot weather，on the other hand，can make it lower.Students in many schools of the United States often get worse in exams in the hot months of the year(July and August)．

    Weather also has a strong influence (影响)on people's feelings.Winter may be a bad time for thin people.They usually feel cold during these months.They might feel unhappy during cold weather.But fat people may have a hard time in hot summer.At about 18℃，people feel more comfortable.

    Are you feeling sad，tired，or unhappy today？It may be the weather's problem.

    SoFi is a special "fish". It is 47 centimeters long. It is all white. It has a small round head. What kind of fish is it? Actually, SoFi is a soft robotic fish. Scientists from MIT made it look like a real fish. They want to use it to study sea animals when the ocean environment changes.

    SoFi's skin is made of a kind of rubber. It's soft. The robotic fish's head is 3D printed. There is a camera in its nose and it can take photos and videos underwater. SoFi can swim among real fish. It is quiet. It doesn't scare other fish. It can also turn left and right, and even change its speed.

    Although SoFi is not the first lifelike robotic fish, it is the most advanced of its kind, according to MIT scientists. Many other countries have also made robotic fish, including the UK and China. Scientists said these robotic fish can easily get close to other fish. And other fish can even interact (互动) with them.

    Football is so popular in China. Almost everyone is interested in this sport—the young and the old, boys and girls, and now even robots.

Recently at Hangzhou Guangming Middle School, kids from several schools played football with their robots.

    Robot football is very different from human football. Only two robots play in each match. The field is as big as a ping pong table. One half is black and the other is white. Each robot tries to catch the "football" and score a goal. The robot with more goals wins.

    Gao Linge, a boy from Hangzhou Guangming Middle School, helped make one of the robots for the match.

    "My school bought the main board (主板),"said Gao, 14. "Then I decided what my robot looked like and made a computer program for it."

    Gao's robot was eight centimeters tall and had two arms. It had four sensors (传感器) to "see" and "kick" the "football".

    Ying Xuehai, a 12-year-old student from Gao's school, also made a robot. His robot played against Gao's. The match decided who would go to the final game. Ying lost the game. So he gave many of his robot's parts to Gao.

    Even so, Gao's robot didn't win the final. It played well in the first five minutes. Then it slowed down. By the end of the match, it could hardly move. What was wrong? Gao and Ying found the problem—the robot ran out of batteries (电池)!

    "We'll solve the problem and beat the other schools next time!" said the two boys.

Everybody dreams. But only some people remember their dreams. Our dreams often include all the senses —- smells, sounds, sights, tastes and things we touch .Sometimes we dream the same dream over and over again.

    Early in the twentieth century, two famous scientists developed their personal ideas about dreams. Austrian psychiatrist (奥地利心理学家) Sigmund Freud wrote a book called "The Interpretation (诠释) of Dreams" in 1900. Freud believed people often dream about things they want but can't have. Swiss (瑞士) psychiatrist Carl Jung worked closely with Freud for several years, but he believed dreams provide solutions to problems we face when we are awake.

    Other researchers are studying how dreaming helps our bodies work with problems and very sad emotions (感情). Robert Stickgold is a professor of psychiatry (心理学教授) at Harvard University in Massachusetts. He says that when we dream, the brain is trying to make sense of the world. He does not agree with Sigmund Freud that dreaming is the way we express our hidden feelings and wishes.

    Scientists believe it is important to keep researching dreams. Doctor Stickgold says it's more than one hundred years since Sigmund Freud wrote his important book about dreaming. Yet there is still no agreement on exactly how the brain works when we are dreaming or why we dream.