Scientists think they have the answer to a puzzle that confused even Charles Darwin: How flowers evolved and spread to become the most important plants on earth.
Flowering plants, or angiosperms (被子植物), make up about 90% of all living plant species,but how they did this has been a mystery. New research suggests it is due to genome (基因组) size.
Hundreds of millions of years ago,the earth was dominated by ferns (蕨类)and conifers(针叶树) - they were the main plants on the earth. Then, about 150 million years ago, the first flowering plants appeared on earth. They quickly spread to all parts of the world.
Why angiosperms were successful and diverse on earth has been debated for centuries.Charles Darwin himself called it a "mystery", fearing this apparent sudden change might challenge his theory of evolution.
Kevin Simonin from San Francisco State University in California US and other researchers analyzed data held by the Royal Botanic Gardens, Kew, on the genome size of hundreds of plants, including flowering plants, gymnosperms (a group of plants including conifers) and ferns. They then compared genome size with anatomical (结构上的) features. This provides "strong evidence" that the success and rapid spread of flowering plants around the world is due to "genome downsizing".
By reducing the size of the genome, which is contained within the nucleus (核) of the cell, plants can build smaller cells. The researchers say genome-downsizing happened only in the angiosperms, and this was "a necessary condition for rapid growth rates among land plants".
1.What do we know about angiosperms? ______
A.They are superior in number among all living plant species.
B.They controlled the earth for hundreds of millions of years.
C.They challenge Charles Darwin's theory.
D.They are extinct plants in the world.
2.It can be implied that ______ .
A.Simonin works in the Royal Botanic Gardens Kew
B.Simonin is probably an American biologist
C.Darwin was confident of his theory of evolution
D.Darwin succeeded in figuring out the flower evolution
3.What contributed to the success and diversity of angiosperms? ______
A.The weaker ferns and conifer.
B.The larger nucleus.
C.The stronger cell.
D.The smaller genome.
4.What can be a suitable title of this passage? ______
A.Why were gymnosperms successful on earth?
B.What puzzle confused even Charles Darwin?
C.Why angiosperms dominated the earth?
D.When angiosperms outnumbered conifers and Ferns?
The development of a V-shaped fuel-efficient airplane design known as the Flying-V will be funded by Dutch national carrier KLM Royal Dutch Airlines.
To improve the sustainability (持续性) of air travel, the Flying-V was developed by researchers at Delft University of Technology in the Netherlands, also known as TU Delft.
Its futuristic design puts the passenger cabin into the wings. It's said the plane will use 20% less fuel than the Airbus A350-9-while carrying a similar number of passengers.
"In recent years, KLM has developed as a pioneer in sustainability within its airline industry," said Pieter Elbers, CEO and president of KLM. "We are proud of our progressive relationship with TU Delft".
"Air travel is contributing about 2.5% of global CO₂ emissions (排放物), and the industry is still growing, so we really need to look at more sustainable airplanes," said TU Delft project leader Roelof Vos.
"We cannot electrify planes, as electrified airplanes become way too heavy and you can't fly people across the Atlantic on electric airplanes- not now, not in 30 years," Vos said. "So we have to come up with new technologies that reduce fuel burning in a different way."
"We've been flying traditional airplanes for decades now, but it seems like they are reaching the limit in terms of energy efficiency," he said."The new design actively contributes to the lift of the airplane, and creates less air drag."
The plane's increased fuel efficiency is largely a result of its design, Vos explained.
The researchers hope to fly a model this September, Vos said, while the new cabin design will be open to the public at Amsterdam Airport Schiphol in October. The completed plane is expected to enter service between 2040 and 2050.
1.What can we infer from the text? ______
A.Flying-V was developed by KLM Royal Dutch Airlines.
B.Researchers at TU Delft have raised enough money.
C.20% of the passengers will sit in Flying-V's wings.
D.KLM plays an important role in sustainability.
2.Why sustainable planes are needed? ______
A.To save electricity.
B.To reduce global CO₂ emissions.
C.To make air travel more affordable.
D.To develop air industry.
3.How does the Flying-V save energy? ______
A.It's the V-shaped design that makes a big difference.
B.The idea of electrified airplanes is applied to its development.
C.It depends on a kind of more efficient fuel.
D.Its futuristic design leads to a limited number of passengers.
4.What's the purpose of the text? ______
A.To instruct us the importance of environment protection.
B.To inspire us to explore the unknown area of technology.
C.To inform us of the fuel-efficient Flying-V.
D.To appeal to us to raise fund for technology.
Growing up in England with a British father and a Chinese mother, I've enjoyed food from both countries ever since I was able to hold a knife and fork and chopsticks!
Mum has sweet memories of the food from her home town in Sichuan, and often cooks spicy dishes.Thanks to this, Dad has come to love hot pot! But there are still some dishes that Dad dare not try even after many years of marriage to my mother. Even today he still does not take to eating things like chicken feet.
But I enjoy that sort of food myself. Last week, I went to the butcher's and asked, "Do you have pigs' ears?" "No," the butcher said, pulling at his own ears, "just these ordinary ones." He must have thought I was joking.
Dad can cook a super "full English breakfast" of bacon, eggs, beans, sausages and toast with butter. Mum and I just have to find a way to get him into the kitchen! He also does a typical Sunday roast.We all love roast beef and vegetables.
I'll never forget my first visit to China. Mum encouraged me to try different kinds of food. But just when I thought I could deal with all Chinese food, I came across stinky tofu, a horrible grey thing that looked and smelt like a burnt sports shoe. I gathered all my courage to take a bite and was amazed to find it wasn't so bad. It reminded me of blue cheese, a similarly strong smelling type of food you either love or hate. Maybe I'll fall in love with stinky tofu, someday.
People say that one man's meat is another man's poison, but I feel at home with food from both my cultures.
1.What can we learn from this passage? ______
A.I have enjoyed the food from two cultures since a little child.
B.Because of my Mum, Dad loves all kinds of Chinese food.
C.We all like roast beef and vegetables except Mum.
D.I have fallen in love with the stinky tofu now.
2.What kind of person did the butcher probably think the author was? ______
A.Generous. B.Mean.
C.Humorous. D.Serious.
3.What does the underlined part in paragraph 2 probably mean? ______
A.Resist. B.Like.
C.Allow. D.Mind.
4.What's the passage mainly about? ______
A.Comparing two different cultures.
B.Trying some different foods.
C.Different eating habits in China and Britain.
D.The eating experiences of a mixed-race family.
Modern people are paying more attention to exercise and many celebrities are leading the trend, while in ancient China there were also many fitness lovers.
Lu You: chosho
As a noted productive poet, Lu You from the Song Dynasty wrote more than 20,000 poems in his lifetime. According to historical records, he lived to 85 years old, the longest living poet in the Song Dynasty.
However, Lu You was weak as a child. During his later years, Lu You started the body building called chosho. Chosho was quite popular in ancient times, which was not roaring or whistling, but an elegant, serious and skillful health method. People opened their body, breathed in deep and then breathed out with a long and loud cry in rhyme.
Su Dongpo: long run, five kilometers per day
The great Song Dynasty poet Su Dongpo, or Su Shi preferred to take long runs, and he thought that only by moving your body regularly could you have a strong body.
He would slow down when he breathed hard, and speed up when his breath balanced. Su Dongpo would run until he was sweaty, hot, blood circulating and limbs feeling refreshed.
Huyan Zan: cold bath
There was an annual festival in November during the early Tang Dynasty (618-907)called "Pouring cold", where a group of strong men, nearly bare, sang and danced in the street while crowds poured cold water on them. The festival, a sacrifice to god, was thought to be helpful to body building.
During the Song Dynasty, Huyan Zan recovered the tradition by removing the singing and dancing parts and keeping the pouring cold water part, as a way to exercise his kids' physical bodies.
1.What would Lu You do when doing chosho exercise? ______
A.Scream after opening his body.
B.Make a long and loud roar.
C.Whistle for a long time.
D.Breathe deep and shout with a rhyme.
2.While Su Dongpo was running, he ______ .
A.adjusted his running speed according to his breath
B.kept running at a high speed all the way
C.would run until his body was tired
D.practiced Qigong during the course of running
3.Why did Huyan Zan have his kids do a cold bath? ______
A.To teach them the hardship of life.
B.To honor his general-inherited family.
C.To make them have a healthy body.
D.To expect them to have a long life.
Being highly successful in any field is pretty rare. It takes a combination of natural talent, luck, determination, and plenty of outside support for someone to make it big in sports, entertainment, or business. But what if competing is all that matters to you, whether you are likely to succeed or not? This was the goal of Michael Eddie the Eagle Edwards, and that he reached that goal was an amazing achievement.
Born in the U.K. in 1963, Michael was an enthusiastic downhill skier whose dream was to compete for Britain in world-class competitions. He would have liked to represent his country in the 1984 Winter Olympics, but there were a large number of downhill competitors, and Edwards didn't qualify. Seeing his chance elsewhere, he switched to ski jumping. Ski jumping didn't cost nearly as much, and there was almost no competition for a place on the Britain team.
But number of hurdles (障碍)could have meant the end of Edwards' dream. He weighed more than most competitors, which put him at a disadvantage. He had no financial support for his training. Poor eyesight meant that he had to wear glasses under his goggles (护目镜)- not a good thing when they steamed up at high altitudes. But he couldn't let any of this discourage him. He saw himself as a true lover of the sport who simply wanted the chance to compete. Winning wasn't the point. Having the opportunity to try was all he cared about. And nothing could stop him from trying.
In the end, Edwards took 55th place in the 1987 World Championships. He then went on to the Calgary Olympics in 1988, where he finished last in both of his events. Many athletes would have been embarrassed by this result, but he is proud of his achievement to this day. His determination to fight against all the odds made him a global hero, and in 2016, the inspiring film Eddie the Eagle was made about his life.
1.What is the purpose of the first paragraph?
A. To add some background information.
B. To uncover the secret of success.
C. To expect an answer from readers.
D. To introduce the topic.
2.Why did Michael Edwards choose ski jumping?
A. It took less skill.
B. The equipment was cheaper.
C. There was little competition.
D. It was easy to win the championship.
3.After the Calgary Olympics, Edwards _________.
A. felt he had reached his goal
B. was embarrassed by his results
C. switched to film making
D. was glad it was over
4.What made Michael Edwards outstanding?
A. His determination to win.
B. His enthusiasm for the sport.
C. His attitude towards the Olympics.
D. His ability to overcome physical disabilities.
The killdeer, a small bird known for its high-pitched(声调高的)call, could lead to the cancellation(取消) of one of Canada’ biggest music festivals.
The first hint of trouble for Ottawa’s Bluesfest, an outdoor festival that draws around 300,000 people each year, came last week after workers at the site found one of the birds.It had laid four eggs nearby, effectively claiming the main stage area as its nesting ground.“This is one of the most challenging problems we’ve been presented with, but we feel we can work through this,” said Mark Monahan, executive director of the festival.“Anything that changes the schedule has a major effect, so we’re taking it very seriously.”
The discovery meant that government officials rushed to protect the nest and the eggs, hiring a security guard to watch over them 24 hours a day.
Environmentalists were also brought in.“We don’t know when the eggs might hatch,” said Monahan. What is known is that the young killdeer will likely leave the nest soon after they are hatched, leading many to hope that the eggs hatch in the next day or so.
The festival is now seeking permission from Environment Canada to relocate(搬迁)the nest some 50 meters away or take it to a wildlife center.Moving the nest would also ensure the bird and its young would be protected during the festival’s 11-day run, said Monahan. It’s highly likely that the festival’s thousands of attendees would cause huge problems for the bird and its eggs.Monahan was confident that the festival would go on as planned, however.“Most of the people we’re working with are looking for a positive solution,” Monahan said.“There is no one saying that the festival can’t go on.”
As news of the dilemma spread, it left residents divided. Some supported the bird, saying that moving the nest might result in the eggs being abandoned.Others expressed annoyance that protecting the eggs of the small bird, which is widespread across North America, was risking an annual festival that contributes millions of dollars to the local economy.
The killdeer’s tendency to build its nest in open fields or flat areas has caused issues in other areas of the US: earlier this year, construction of a health center in Wisconsin was temporarily stopped after a killdeer and its four eggs were discovered.
1.What can we learn about Bluesfest?
A.It is the first music festival in Canada.
B.It is an important event for music lovers.
C.It is a music festival held every two years.
D.It is a challenging outdoor activity in Ottawa.
2.What was especially challenging for Bluesfest this year?
A.Pressure from the government.
B.Disagreements with the public.
C.The need to protect the bird’s eggs.
D.The lack of experience in hosting the event.
3.How did the festival plan to deal with the problem?
A.Move the nest to another place. B.Ask government officials for help.
C.Seek advice from environmentalists. D.Hire security guards to protect the eggs.
4.The underlined word “dilemma” is closest in meaning to “______”.
A.a difficult situation B.an extreme situation
C.a dangerous situation D.an encouraging situation