The fact that your hair turns grey because of stress is nothing more than an old wives' tale. It's true that stress isn't good for you, but it's not going to turn you into a silver fox just yet. In fact, the answer comes from the cells in your hair. These are what decide the color and, eventually, the fade to grey.
Most of us start to notice our first grey hairs by the time we hit our thirties. A general rule to go by is that by the age of 50, half of the population will have lost the color in 50 percent of their hair.
But why does it happen? Firstly, we need to understand how hair gets its color.
Your hair is made up of cells called melanocytes (黑色素细胞) which produce pigments (色素) as they grow into the hair fiber. There are two different types of melanins: eumelanins and pheomelanins. The former produces black and brown pigments, while the latter produces red and yellow pigments. The exact amount of these pigments decide whether a person has black, brown, blonde or red hair.
As we age, the ability of the melanocytes to produce more pigments weakens. That's because our hair grows in different periods.
The growing period lasts between three and five years, after which our follicles (毛囊) turn off for about three months to rest and get ready to grow more hairs. This goes round and round and, after a time, our bodies aren't as good at producing new hairs.
Scientists are continuing to try and find ways to prevent greying hair. A team of scientists in France is working to try and stop the melanocytes from being damaged at the end of each hair cycle. They are trying to use a special enzyme (酶) to protect the cells from damage. If successful, it could lead the way for new products that keep our hair full of color for years to come.
1.What does the phrase ''an old wives' tale'' in Paragraph 1 probably mean?
A.A wrong belief B.A useful talk
C.A scientific rule D.A helpful experience
2.What do we know about red hair?
A.It doesn’t turn grey as people get older.
B.It contains more pheomelanins than eumelanins.
C.The amount of pigments in it doesn't change over time.
D.People with red hair have weaker ability to produce pigments.
3.What do the French scientists aim to do?
A.To repair damaged hair follicles.
B.To protect hair cells against damage.
C.To shorten the hair cycle to protect the hair.
D.To study the relationship between health and hair color.
4.What can be a suitable title for the text?
A.Grey Hair: a Symbol of Huge Pressure.
B.Grey Hair: a Symbol of Declining Health.
C.Cells: the Cause of New Hair Growth.
D.Cells:the Cause of Color Change of Hair.
Emilia Dobek traces her interest in space and the universe back to third grade when she and her father watched a blood moon — a total lunar eclipse (月食)---on the roof of their house.
Now a seven-grader at East Prairie Elementary School, Dobek recently won the national Discovery Education Beyond Challenge by designing a space station for traveling to Mars. She says that night watching the lunar eclipse launched a passion in her that has yet to run out of fuel.
So, when her teacher, Andrea Smeeton, received information about the national challenge, Smeeton said she immediately had one student in mind. “I knew she would love the challenge and that she would go way beyond in her research,” Smeeton said. “She immediately started researching bone density of astronauts and how to have sustenance on Mars.”
“My design will ensure the safety of the astronauts but also make sure their comfort is out of this world,” said Dobek. Dobck’s design calls for building the MSS or Mars Storage Station to accommodate the need for abundant supplies. She explains how her spacecraft—the Adventurer—will get into a space station before flying to the MSS to get supplies. Her design includes the SGF or SelfGrowing Farm, and she details how it would work with the elements on Mars.
Then there is physical and leisure activity for the astronauts under Dobck’s design. A. simulator (模拟器) allows astronauts to choose their exercise machine and virtual reality environment. Rooms have circular ceilings, she says, so astronauts will be able to watch downloaded shows and even see places on Earth, such as their homes. Chief among her immediate goals, she said, is to inspire with this project. want to tell other kids to follow their passions,” Dobek said. “Whatever they want to do, they should kind of just push for it. They should always try their best.”
1.What launched Dobek’s passion for space and the universe?
A.Winning the national challenge.
B.Observing the lunar eclipse with her father.
C.Studying with her teacher Andrea Smeeton.
D.Designing a space station for traveling to Mars.
2.How can astronauts entertain themselves in Dobek’s design?
A.By exercising in outer space. B.By playing virtual reality games.
C.By appreciating places on Earth. D.By enjoying shows of their homes.
3.What is Dobek’s major aim with her project?
A.To realize her immediate goals.
B.To create a leisure design for astronauts.
C.To get inspired by the national challenge.
D.To encourage others to pursue their interest.
4.What is the best title for this passage?
A.New Space Station Design
B.Leisure Activities for Astronauts
C.7th-grader Won National Prize
D.Patient Teacher Motivated Innovation.
Knowing what not to do at checkout and properly preparing for it can turn a potentially heated situation into a quick thank you and goodbye. Below we compiled a list of things you should remember at hotel checkout.
1. Don’t be late to checkout
Hotels may add an outrageously high price for being just a half-hour late. If you know you won’t make the cutoff time, it never hurts to call ahead and try to negotiate a potential charge.
2. Don’t forget to double check the room and safe
Make sure you don’t leave anything behind. If you have an early flight or checkout time, pack up as much as you can the night before so that last-minute rush isn’t too hurried. Also, be sure to take out anything in the room safe.
3. Don’t freak out
Spitting venom (毒液) at the assistant manager standing behind the front desk probably won’t help when dealing with an unexpected item on the bill. Being empathetic about how difficult it can be to deal with annoyed customers will likely go much further.
4. Don’t pay with cash or debit card (借记卡)
Disputing your bill after paying with cash is a lot harder than working with a credit card company to get a charge back. If you pay with a debit card, you may not have the protection to challenge a charge.
5. Don’t have the hotel call you a cab
If you want to save a few dollars, plan ahead and check if a ride-sharing service is going to be cheaper than a cab to the airport.
1.What may the hotel do if you are late for the checkout?
A.Negotiate a potential price.
B.Call ahead and cancel the reservation.
C.Charge extra money.
D.Give the room to other customers.
2.What should you do when the receptionist meets angry customers?
A.Spit at the assistant manager. B.Argue with the front desk.
C.Show understanding to the situation. D.Go much further away from it.
3.Why is it a good idea to use a ride-sharing service to get to the airport?
A.It helps the cab save dollars.
B.It reduces the burden of the hotel.
C.It is easy to get a charge back.
D.It costs the customers less money.
假设你是李华，你的英国笔友David对国内最近很受欢迎的节目《中国诗词大会》很感兴趣，写信向你了解该节目并请教学习古诗的方法。请你用英语给他回一封邮件。内容包括：
1.节目简介： 2016年首播。今年的冠军是来自上海的16岁中学生武亦姝。
2.节目意义。
3.学习古诗的建议，
注意：1.词数100左右；
2.可以适当增加细节，以使行文连贯；
3.开头和结尾已给出，不计入总词数；
4.参考词汇：中国诗词大会Chinese Poetry Competition
Dear David.
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
___________________________________________________________________________
Yours,
Li Hua
假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏字符号(Λ)，并在其下面写出该加的词。
删除：把多余的词用斜线(＼)划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：
1. 每处错误及其修改均仅限一词；
2. 只允许修改10处，多者(从第11处起)不计分。
Dear Editor,
I'm writing to tell you about a shocked incident that happened in Beijing Zoo in the afternoon of Feb 23rd. I was visiting the zoo that afternoon while I heard bears roaring terribly. I hurried to the place where the bears lived at. I saw the black bear badly injured and one of them rolling on the ground painfully. It was hurt too serious to move a foot.
The people around are shocked, angry and blaming the wrongdoer. I learned that was a student from a famous university in Beijing who caused the trouble. He poured sulphuric acid(硫酸) onto the bears, or pretending to feed them.
What an shame! Animals are our friends and something must be done to prevent them from being injured.
Sincerely yours,
Li Hua
阅读下面材料，在空格处填入1个适当的单词或使用括号中单词的正确形式。
China launched the Shenzhou Ⅺ manned spacecraft on Monday morning to transport two astronauts to the Tiangong Ⅱ space laboratory. The spacecraft 1.(send) skyward at 7:30 am atop a Long March 2F rocket from the Jiuquan Satellite Launch Center in Northwest China, 2.(carry) two male astronauts — Jing Haipeng and Chen Dong. After the launch, the spacecraft will travel two days before docking with the Tiangong Ⅱ, 3.was lifted from the Jiuquan center in mid-September. Then the astronauts will enter the space lab and stay there 4.30 days, and it will be the longest space stay by Chinese astronauts.
The core 5.(task) of the Shenzhou Ⅺ mission are to test rendezvous and docking technologies for the country’s 6.(plan) space station, to verify the life-support capability of the spacecraft-space lab combination as well as conduct 7.(science) research and test engineering experiments.
China is 8.third country in the world that has 9.(independent) fulfilled manned spaceflight following the former Soviet Union and the United States and 10.(it) space program aims to place a permanent manned space station, into service around 2022.
