Planet Earth would be a scary place for humans if dinosaurs still ruled the world.
Though there are still some traces of life from the Jurassic Period, the Age of Dinosaurs more than 65 million years ago.
This mass extinction is believed to be the result of an asteriod（小行星）hitting Earth. A new report by the journal Biological Reviews called " The Extinction of Dinosaurs” concludes that this impact was, indeed, the cause of the dinosaurs’ demise. But the space blast(爆炸) wasn't the only reason these creatures aren't still around today.
Dinosaurs need food to survive. Meat-eating monsters like the Tyrannosaurus Rex(霸王龙) were at the top of the food chain, and fed off plant eaters like the horned Triceratops (三角恐龙). These herbivores (食草动物) were decreasing in population after the asteroid hit Earth, which left the meat-eating species less food to survive on. “In any ecosystem where you remove links to key species, that community has problems," Richard Butler, one of the review's authors, told National Ceographic.
While the herbivore population was going down, Earth's temperatures were rising when volcanoes erupted. Hot vapors and gases began wiping out some of the dinosaur population and weakening the survivors.
These changes made the asteroid's impact especially powerful. It caused more volcanoes to erupt, heated up Earth's atmosphere, and led to a sharp drop in the level of oxygen in the oceans.
With the dinosaurs gone, mammals(哺乳动物) began to evolve into bigger and more diverse species. Many animals we see today, like birds, sharks, and even some cats and dogs, appeared after the asteroid hit Earth. But none rule Earth quite like the dinosaurs did.. Which of the following words can replace the underlined word’’ demise" in Paragraph 2?
| A．Death. | B．Evolvement. |
| C．Presence. | D．Decrease. |
According to what Richard Butler said, what caused dinosaurs to die out?
| A．A shortage of clean water. |
| B．A break in the food chain. |
| C．A small variety of animals. |
| D．The constant warming climate. |
What was the negative effect of the asteroid hitting Earth?
| A．Oceans became too hot for animals. |
| B．There was less oxygen in the oceans. |
| C．Earth's climate became violent. |
| D．The majority of the plants gradually died out. |
The text is mainly about .
| A．the evolvement of mammals on Earth |
| B．the gradual process of climate change |
| C．the importance of the balance of ecosystem |
| D．the cause of the extinction of the dinosaurs |
A new study suggests that the more teenagers watch television, the more likely they are to develop depression (抑郁) as young adults. But the extent to which TV may be to blame is a question that the study leaves unanswered.
The researchers used a national long term survey of adolescent health to investigate the relationship between media use and depression. They based their findings on more than 4, 000 adolescents who were not depressed when the survey began in 1995.
As part of the survey, the young people were asked how many hours of television or videos they watched daily. They were also asked how often they played computer games and listened to the radio.
Media use totaled an average of 5 and one half hours a day. More than 2 hours of that was spent watching TV.
7 years later, in 2002, more than 7 percent of the young people had signs of depression. The average age at that time was 21.
Brian Primack at the University of Pittsburgh Medical School was the lead author of the new study. He says every extra hour of television meant an 8 percent increase in the chances of developing signs of depression.
The researchers say they did not find any such relationship with the use of other media such as movies, video games or radio. But the study did find that young men were more likely than young women to develop depression given the same amount of media use.
Doctor Primack says the study did not explore why watching TV causes depression. But one possibility, he says, is that it may take time away from activities that could help prevent depression, like sports and socializing. It might also interfere with sleep, he says, and that could have an influence.
The study was just published in the Archives of General Psychiatry.
In December, the journal Social Indicators Research published a study of activities that help lead to happy lives. Sociologists from the University of Maryland found that people who describe themselves as happy spend less time watching television than unhappy people. The study found that happy people are more likely to be socially active, to read, to attend religious services and to vote.According to the first paragraph, what remains unsolved in the new study?
| A．Who is more likely to be influenced by TV. |
| B．How much teenagers are depressed by TV. |
| C．Whether teenagers are influenced by TV. |
| D．What should be done to help the teenagers. |
What can be inferred from the seventh paragraph?
| A．Depression is not related to the use of other media than TV. |
| B．Every extra hour of media use increases the chance of depression. |
| C．Longer use of media other than TV doesn't increase the chance of depression. |
| D．The influence of movies, video games and radio on depression varies respectively. |
The study done by the sociologists from the University of Maryland was mainly intended to __________.
| A．tell the difference between happy and unhappy people |
| B．prove the relationship between TV and depression |
| C．stress the importance of being socially active |
| D．provide a happy recipe (秘方) for all people |
Each new school year brings fresh reminders of what educators call the summer learning gap. Some call it the summer learning setback. Put simply, it means the longer kids are out of school, the more they forget. The only thing they might gain is weight. Recent studies show that children gain weight more quickly in the summer vacation than when they are in school.
Most American schools follow a traditional nine-month calendar. Students get winter and spring breaks and about ten weeks of summer vacation. Some schools follow a year round calendar. They hold classes for about eight weeks at a time, with a few weeks off in between. But many experts point out that the number of class days in a year-round school is generally the same as in a traditional school.
Last year, a study at Ohio State University reported that year-round students did not learn any more than other students. Lead researcher Paul von Hippel said "year-round schools don't really solve the problem of the summer learning setback. They simply spread it out across the year".
Across the country, research shows that students from poor families fall farther behind over the summer vacation than other students. Experts say this can be prevented. They note that many schools and local governments offer the programs that can help.
But calling them "summer schools" could be a problem. The director of the summer learning center at Johns Hopkins, Ron Fairchild, recently wrote about this issue on his blog.
He said that in American culture, the idea of summer vacation is connected to the beliefs about freedom and the joys of childhood. He said research with groups of different parents in Chicago and Baltimore found that almost all strongly disliked the term summer school. They said it created an image of children being forced to do work they missed during the school year.Which of the following is the, result of the long summer vacation?
| A．Kids become much stronger. |
| B．More kids drop out of school. |
| C．Kids become poor in learning. |
| D．Kids take part in all kinds of activities. |
Some American schools have their vacations __________.
| A．every two months |
| B．every few weeks |
| C．every three months |
| D．every four months |
The study at Ohio State University suggests that __________.
| A．the traditional calendar is better than the year-round one |
| B．the year-round calendar is better than the traditional one |
| C．the traditional calendar is as bad as the year-round one |
| D．the year-round calendar is the same as the traditional one |
According to American culture, during the summer vacation kids __________.
| A．should try their best to improve their lessons |
| B．must choose to take part in one of the programs |
| C．should do what they like and enjoy themselves |
| D．must be forced to make up for their poor lessons |
What exactly are white lions? "They are a color variation of regular lions," says William Swanson, director of animal research at the Cincinnati Zoo, in Ohio.
White lions are the result of a rare color gene mutation (变异). When both a male and a female lion carry the same white genes, there is a good chance that one or more of their cubs (幼兽) will be born with white fur.
Not many lions carry the white mutation. In nature, it's rare. A mutation can make an animal's survival more difficult. For example, being white makes it harder for the animal to mix with itssurroundings. Mutations also can cause physical problems, so those animals generally do not survive long enough to reproduce.
But sometimes white lion cubs are born among wild lions, especially in two areas of South Africa.
In 1975 two white cubs were spotted in the wild in South African reserve. They were seized and sent to a zoo. Today about 500 cubs of those two white lions and a few others known to have the white color gene live around the world in zoos, circuses, farms and private preserves.
White lions may be extremely rare in the wild, but breeders (饲养动物的人) know how to create more of them. This has created serious concern and debate.
White lions continue to exist only because they are inbred by people—fathers and daughters, sisters and brothers. Scientists worry that it also will cause health issues for white lions.
Inbreeding to create white lions as moneymaking attractions is only one concern. Another concern is that some people want to release captive-bred (人工繁殖的) white lions into the wild in South Africa to restore balance to the ecosystem. However, not everyone agrees that releasing these white lions into the wild is a good idea. Dan York of Hillsdale College has been studying white lion genetics and is worried. He says that because so many of today's white lions are inbred, it could spread health problems. If they breed with wild lions, they'll pass on the genetic problems to the wild population.
Instead of releasing captive-bred white lions, York suggests that South Africa concentrate on protecting all of its wild lions. That would ensure the safety of the wild population of lions, which may produce healthy white cubs in the future.It's difficult for a white lion to survive because __________.
a. its fur contrasts sharply with the surroundings
b. the mutation may cause physical problems
c. it is likely to be attacked by wild lions
d. it is hunted by human beings
| A．a, b |
| B．a, d |
| C．a, c |
| D．b, d |
What does the underlined word "inbred" inParagraph 7 probably mean?
| A．kept in enclosed space and unable to run away |
| B．bred in human-controlled environments with restricted settings |
| C．produced by breeding among closely related members |
| D．born among wild lions and kept in the zoo |
One of the reasons for inbreeding white lions is that __________.
| A．they can bring people a profit |
| B．their fur can be of great use |
| C．people want to keep white lions as pets |
| D．people want to study the genes of white lions |
Which of the following agrees with Dan York's opinion?
| A．It's useless studying white lion genetics. |
| B．White lion cubs born among wild lions are more healthy than captive-bred ones. |
| C．White lions shouldn't be kept in zoos or circuses. |
| D．The ecosystem in South Africa is being seriously damaged. |
To a large degree, the measure of our peace of mind is determined by how much we are able to live in the present moment. In spite of what happened yesterday or last year, and what may or may not happen tomorrow, the present moment is where you are—always!
Without question, many of us have mastered the sensitive art of spending much of our lives worrying about a variety of things—all at once. We allow past problems and future concerns to control our present moments, so much that we end up anxious, discouraged, depressed, and hopeless. On the other hand, we also put off our satisfaction, and put off what we should think of first, and our happiness, often convincing ourselves that "someday" will be better than today. Unfortunately, the same mental power that tells us to look toward the future will only repeat themselves so that "someday" never actually arrives. John Lennon once said, "Life is what's happening while we're busy making other plans." When we are busy making other plans, our children are busy growing up, the people we love are moving away and dying, our bodies are getting out of shape, and our dreams are slipping away. In short, we miss our life.
Many people live as if life were dress rehearsal (彩排) for someday in the future. It isn't. In fact, no one has a guarantee that he or she will be here tomorrow. Now is the only time we have, and the only time that we have any control over. When our attention is in the present moment, we push fear from our minds. Fear is the concern over events that might happen in the future—we won't have enough money, our children will get into trouble, we will get old and die, whatever.
To fight against fear, the best method is to learn to bring your attention back to the present. Mark Twain said, "I have been through some terrible things in my life, some of which actually happened. I don't think I can say it any better. Practice keeping yourattention on here, and now. Your efforts will pay off sooner or later."If a person is able to enjoy the present moment, then he __________.
| A．is out of mind |
| B．is in peace of mind |
| C．has forgotten his past |
| D．will ignore his future |
In the writer's eyes, "fear" is the __________.
| A．concern over past problems |
| B．attention on the present. |
| C．worry about what might happen in the future |
| D．anxiety about dress rehearsal |
By using what John Lennon said, the writer intends to __________.
| A．advise people to fix their attention on the present life |
| B．remind people to make good plans for their future |
| C．warn people that their children are growing up |
| D．remind people that their bodies are out of shape |
According to the writer, now is __________.
| A．the only time for us to get rid of what happened yesterday |
| B．the first time for us to look forward to our future |
| C．the only time we have and can control |
| D．the busy time we can make good preparations for the future |
The idea for a science experiment can come from an unusual place. After watching a YouTube video of a dancing bird named Snowball, a scientist in California decided to study the ability of animals to keep the beat.
Bird lovers have long claimed that their pets have rhythm, and there are many videos of dancing birds online. Until now, scientists have suspected that humans are the only animals that can accurately keep rhythm with music.
Thanks to Snowball, that scientific opinion is changing. Snowball is a cockatoo, a kind of parrot, and his favorite song is "Everybody" by the Backstreet Boys. When he hears the song, he moves his feet and rocks his body with the tempo, or pace of the music, as though he is the only bird member of the boy band.
Aniruddh Patel is a neuroscientist, or a scientist who studies how the brain and the nervous system contribute to learning, seeing and other mental abilities. He works at the Neurosciences Institute in San Diego. After seeing Snowball's dance online, Patel visited the cockatoo at the bird rescue facility he's called home for two years. The scientist played "Everybody" for Snowball and also played versions of the song that were sped up or slowed down. Sometimes, Snowball danced too fast or too slowly. Often, when there was a change in tempo, Snowball adjusted his dancing to match the rhythm. In other experiments, scientists have observed the same abilities in preschool children.
Patel isn't the only scientist who has studied Snowball's moves. Adena Schachner, who studies psychology at Harvard University, also wanted to know more about the dancing bird. Schachner's team played different musical pieces for Snowball and a parrot named Alex, as well as eight human volunteers. The scientists observed that the birds and thehumans kept time to the music with about the same accuracy.
Schachner and her team watched thousands of YouTube videos of different animals moving to music. Not all the animals could dance, however. From watching the videos, the scientists observed that only animals that imitate sounds, including 14 parrot species and Asian elephants, accurately moved in time to music.The underlined words "that scientific opinion" in the third paragraph refer to the theory that __________.
| A．birds like Snowball have the ability to keep the beat |
| B．humans are the only animals that can accurately keep rhythm with music |
| C．the brain and the nervous system contribute to some mental abilities |
| D．bird pets can have their special rhythm under human's instruction |
From the fourth paragraph we may know that __________.
| A．Patel is the only scientist who has studied Snowball's moves |
| B．Snowball is able to adjust his dancing to match the rhythm |
| C．Snowball cannot dance to the versions of the song "Everybody" |
| D．it is the brain and the nervous system that control the mental abilities |
The idea of studying animals' ability to keep the beat comes from __________.
| A．bird lovers' discovery |
| B．humans' musical sense |
| C．the same abilities in children |
| D．videos of dancing birds |