We take showers and use the toilet every day to get rid of badly waste. Our brains also need to take a bath every day. How can they do it?
A 2013 study found the answer. Researchers at the LS University of Rochester studied the brains of mice and discovered that they cleaned themselves while the mice slept. A kind of fluid in the brain, called cerebral spinal fluid (CSF, 脑脊液), was found to increase dramatically (显著地) during sleep, washing away waste proteins that had been building up between brain cells in waking hours.
"This study shows that the brain has different functional stales when asleep and when awake," Maiken Nedergaard, the lead researcher, told NBC News. It also explains why we can't seem to think clearly after a sleepless night while a good night's sleep leaves us feeling sharp and refreshed.
Now a new study, published on Oct 31 in Science, digs a little deeper into our brains' self-cleaning procedure. Instead of mice, this time humans were the test subjects.
Researchers at Boston University, US, monitored (监测) the brain waves of 13 healthy adults who were sleeping, using accelerated MRI, which is capable of recording faster changes inside the brain than a regular MRI machine. They found that every 20 seconds, blood flowed out of the brain, making room for a large amount of CSF to come in and "clean". This cycle coincided with(与……一致) the rhythm of the brain's slow waves-an electrical activity that happens when we're in deep sleep.
It's still unknown how these brain activities are connected. But the mere fact that they are connected is exciting enough, since it allows researchers to piece together (拼凑出) possible new explanations for misunderstood diseases.
For example, slow-wave sleep has been proven to play a role in strengthening our memories. This may explain why people with Alzheimer's often have fewer and weaker slow brainwaves. Based on this new study, there could be one more explanation for diseased brains: They are not clean.
Nedergaard, leader of the 2013 study, is also excited about the new findings. "Maybe the most important take-home message is that sleep is a serious thing," she told Scientific American. "You really need to sleep to keep a healthy brain because it links electrical activity to a practical 'housekeeping' function."
1.When the researchers studied the brains of mice, they found __________.
A.CSF in their brains went down when the mice slept
B.CSF carried away waste proteins in their brain during sleep
C.more waste proteins were produced in their brains when asleep
D.the more CSF was in their brains, the fewer waste proteins were
2.What did the researchers discover when they monitored human brain waves?
A.The rhythm of the brain was slower than that of CSF.
B.The brains worked more slowly when asleep.
C.Brains were cleaned when blood flowed out.
D.It took 20 seconds for CSF to clean brains.
3.Which of the following would be the best title for the passage?
A.Connecting Brain Activities B.Cleaning in Your Dreams
C.Having a Good Sleep D.Explaining Diseases
Love on the Phone Line
Most of us want to know what we mean to those who mean everything to us, but how do we know if we don't tell each other? I want to share an experience of mine to tell you when you really love someone, tell them directly.
When I was growing up, I never heard the words "I love you" from my father. If your father never says them to you when you are a child, it gets more and more difficult for him to say those words as you get older. In fact, I never said those words to him, either.
A few years ago, I decided to make the first move. After some thought, I called my father on the phone and said: "Dad, 1 love you!" There was a moment of silence at the other end of the line. "Well, same back at you!" he replied quietly.
"Dad, I know you love me. When you're ready, you'll say it, too," I said with a smile. Then I hang up the phone. But fifteen minutes later, my mother called and asked if everything was "OK", She seemed nervous. "Your father seems to have something to say after answering your call". 1 didn't tell my mother about the call. I just told her it was a secret between us.
A few weeks later, Dad called and ended our phone conversation with the words: "Son, I love you," I was at work during this conversation and tears came to my eyes as I finally "heard" the love. This special moment took our father-son relationship to a new level. Later, we got used to saying "I love you" to each other.
I think if I had not taken the first step, I would have never heard the love from my father.
1.What did the writer do when he decided to show love to his father?
A.He spoke out his love to his father on the phone.
B.He told her mother about his love to his father.
C.He bought some flowers to show love.
D.He made a love card for his father.
2.How did the writer's mother feel when she called him?
A.Happy. B.Exited. C.Nervous. D.Confident.
3.According to the passage, the writer wants to tell us that it's necessary _________.
A.to speak out our love B.to call our parents C.to go home often D.to keep love secret
Best Ways to Improve Online Experience
Zhao Yuchen, Beijing To me, the biggest headache about studying online is my poor internet connection. During one online class, 1 couldn't hear my English teacher's voice and I had to reconnect. It wasted lots of time. Since then, I have checked my network before class every day and asked other family members not to use the internet while I'm in class. |
Qiu Ziyin, Shenzhen During the first day of studying online, I was excited and listened carefully. But I soon realized that my self-discipline (自律) was weak. I've set screen time for all of my electronic devices. At night, I do preview (预习) work for the next day instead of playing with my mobile phone. |
Zhao Jiawen, Shanghai It's important to know how to choose wisely when we pick online courses. For example, I had difficulty understanding certain English grammar points, so I searched for key words on our national cloud learning platform and watched several videos from teachers across China. It's good for us to get different teachers. |
Zhang Penghui, Heilongjiang Online learning takes strong self-discipline and willpower. There are lots of distractions (分心) while studying at home. My mom likes to offer me snacks and drinks, which sometimes distracts me from listening during my classes. A quiet room and clean desk can help us stay focused. |
1.Who does preview work for the next day a night?
A.Zhao Yuchen. B.Qiu Ziyin. C.Zhao Jiawen. D.Zhang Penghui.
2.Zhao Yuchen __________ while having class online.
A.has asked other family members not to use the internet
B.watches several video from teachers
C.likes to have snacks and drinks
D.plays with the mobile phone
3.Zhang Penghui thinks that __________.
A.students' self discipline is weak
B.it's good for students to get different teachers from China
C.a quiet room and clean desk can help students stay focused
D.the biggest problem about studying online is the poor internet connection
Changing Makes You More Confident
I used to hate being called upon in class mainly because I didn't like attention drawn to myself. And unless otherwise assigned (指定) a seat by the teacher, I always _______ to sit at the back of the classroom.
All this changed after I joined a sports team. It began when a teacher suggested I try out for the basketball team. At first I thought it was a _______ idea because I didn't have a good sense of balance, nor did I have the _______ to keep pace with the others on the team and they would laugh at me. But for the teacher who kept insisting on my "going for it", I wouldn't have decided to give it a try.
When I first started _______ the practice sessions, I didn't even know the rules of the game, much less what I was doing. Sometimes I'd get confused and take a shot at the wrong _______ - which made me feel really stupid. Fortunately, I wasn't the only one "new" at the game, so I decided to focus on learning the game, do my best at each practice session, and not be too hard on myself for the things I didn't know "just yet".
I practiced and practiced. Soon I knew the _______ and the "moves". Being part of a team was fun and motivating (激励, 动力). With time, I learned how to play and made friends in the process-friends who respected my efforts to work hard and be a team player. 1 never had so much fun!
With my improved self-confidence comes more _______ from teachers and classmates. I have gone from "_______" in the back of the classroom and not wanting to call attention to myself, to raising my hand-even when I sometimes wasn't 100 percent sure. I had the right answer. Now I have more self-confidence in myself.
1.A.hoped B.agreed C.meant D.chose
2.A.good B.crazy C.common D.bright
3.A.ability B.night C.chance D.patience
4.A.enjoying B.preparing C.attending D.watching
5.A.direction B.decision C.competition D.discussion
6.A.steps B.rules C.orders D.games
7.A.praise B.advice C.comfort D.courage
8.A.dreaming B.talking C.fighting D.hiding
— Excuse me, could you tell me__________.
— Sure. Go down the street, and you can find it at the second crossing.
A.where is the supermarket B.where was the supermarket
C.where the supermarket is D.where the supermarket was
The environment in my hometown is improving because many trees __________ every year.
A.plant B.are planted C.planted D.were planted
