Do stars only appear at night? The answer is no .Venus （金星） is the one and only star that can be seen in the daytime. It shone at its brightest in the night sky on February 17^th, 2017.

    Venus is the second planet from the sun in our solar system. It is the second brightest natural object, behind Earth's moon, in the night sky. Why is it so bright?

    First of all, Venus is the closest planet to Earth. It is also covered by highly reflective （反射的）clouds, which can reflect about 70 percent of the sunlight striking（照射） it, almost twice as much as Earth does.

    Some called 2017 the year of Venus, because the planet is at its brightest when it goes further away from the sun, and nearer to Earth. The brightest moment happened once in February, and happened again, during daylight, on April 30^th.

    If Venus is so bright and close to us, isn't it a better choice for human exploration than Mars? It is closer to Earth than Mars and it's closer to Earth in size. The closer distance to the sun means solar power would be easier to generate （产生） as well.

    However, with a temperature of about 465℃on the surface, Venus is the hottest planet in our solar system!

    But scientists never give up. Recently, a team of NASA and Russian scientists created new computer equipment that can stand the temperature of 480℃. It can work under Venus-like conditions for almost 22 days.

    The next step, according to the scientists, is to send a probe（探测器）to Venus by 2025.

    Big ocean fish have almost been endangered since the start of business fishing in the 1950s. The scientists found that the number of large fish has dropped by 90 percent in the past fifty years. The study took ten years. The researchers collected records from fishing businesses and governments around the world. The magazine Nature published (发表) the findings.

    The scientists say the common way called long line(多钩长线) fishing is especially harmful to large fish. This way includes many fishing lines that are connected (连接) to one boat. If these lines are joined together, they can reach one hundred kilometers. They hold thousands of sharp metal hooks to catch fish. Long line fishing is especially common in the Japanese fishing industry. Records showed that Japanese boats used to catch about ten fish for every one hundred hooks. The study says long line fishing boats now might catch one fish per hundred hooks.

    The scientists say business fishing can destroy groups of fish much faster than in the past. The study suggests that large fish can disappear almost completely from new fishing areas within ten to fifteen years. Ocean life systems could be destroyed.

    It's not the only worry that the number of large fish is becoming smaller and smaller. What's worse, they are smaller in size than their ancestors (祖先).

    Beautysleep is a real thing, researches have shown that people who have enough sleeplook more attractive (有魅力的) to others.

    A few badnights are enough to make a person look especially "more ugly", theirsleep experiments show.

    Theresearchers asked 25 university students to join in their sleep experiment.They were asked to get a good night's sleep for two nights.

    A weeklater, they were asked to sleep for only four hour every night for two nightsin a row. The researchers took make—up free (素颜) photos of the volunteers afterboth the good and the bad sleep.

    Next, theyasked 122 strangers to have a look at the photos and judge (评价) them on attractiveness, health,and sleepiness, as well as asking them: "How much would you like to makefriends with this person in the picture?"

    Thestrangers were good at judging whether the person they were looking at wastired, and if he was sleepy, his attractiveness score would be low.

    Thestrangers also said they wouldn't want tosocialize with the tiredstudents. The researchers say this is natural for people. An unhealthy-lookingface makes people run away. In other words, people don't want to hang aroundwith people who might be ill.

    Dr Brewer,an expert at the University of Liverpool said: "Judgment of attractivenessis often unconscious (无意识的), but we all do it, and we are able to judge on even somethingsmall like whether someone looks tired or unhealthy. This study is a goodreminder of how important sleep is to us."

Twenty percent of all the water that goes into oceans around the world comes from one river — the Amazon.

The Amazon River{#blank#}1{#/blank#}from the Andes Mountains in Peru.It travels about 6，400 kilometres to the Atlantic Ocean.It is the largest river in the world.It is{#blank#}2{#/blank#}the second longest.Most of the Amazon's water comes from rain.During the rainy season, parts of the{#blank#}3{#/blank#}are 190 kilometres wide.

The Amazon River goes through the world's largest{#blank#}4{#/blank#}forest.The Amazon rain forest is home to the largest{#blank#}5{#/blank#}of plants and animal species(物种) on Earth.There are 2.5 million kinds of insects,{#blank#}6{#/blank#} the world's largest ant.At least 3，000 kinds of fish and one­fifth of all the bird species in the world{#blank#}7{#/blank#}there.Some of the Amazon's animals are{#blank#}8{#/blank#}， such as the anaconda(水蟒), so people should be careful.There are also gentle animals, like the sloth(树懒){#blank#}9{#/blank#} the pink dolphin.

The Amazon is very important to Earth.There are still many kinds of animals and plants there that we don't know about.If we lose the Amazon, we will{#blank#}10{#/blank#}a big part of life on Earth.

My name is Linda. This is a photo of my family. Look! The old woman is my grandma. The woman in red is my mother. The man in black is my father, Harry Smith. He is a teacher in a school. This tall(高的) man is my uncle, David Brown. He is my mother's brother. He is next to my mother. I'm in white. My family is very happy, I love my family very much. 

What is the most stressful thing in school? It is probably exams. Exams can put us under a lot of pressure. But some students do well under pressure while others feel terrible. {#blank#}1{#/blank#}

It all comes down to dopamine (多巴胺). {#blank#}2{#/blank#} It has many important roles: influencing memory, attention. and how we learn. Our brains work best when there is an even balance of dopamine—not too much or too little. The brain controls dopamine in two ways. It either takes out dopamine quickly, or gradually. Exam success can be related to how fast dopamine goes back to an even balance.

 {#blank#}3{#/blank#} if you become stressed, your brain will start to have too much dopamine. {#blank#}4{#/blank#} The quicker you are able to go back to an even balance of dopamine, the quicker you can fix yourself perform better on a test. 

Scientists found that, during a test, people who slowly got back to an even balance of dopamine scored 8 percent lower. {#blank#}5{#/blank#} The answer is yes. So don't fear, there is some good news. The study also found that the more practice you get, the less stressed you'll be. So, it turns out that practice really does make perfect.

A．What happens when we sit for an exam?

B．It is like a cup flowing over with water.

C．So, why do some students perform better under stress?

D．That's the difference between a good mark and a bad mark.

E．Dopamine is a chemical in our brain that sends information to our body.

F．Is there anything that can help change the speed of dopamine getting into our body?