Young sunflowers turn and swing every day. New findings add to evidence that the plants are animal-like.
Harmer, a professor in the University of California at Davis, Department of Plant Biology, carried out a series of experiments on sunflowers in the field, in pots outdoors and in indoor growth chambers.
By staking plants so that they could not move, Harmer showed that he could destroy their ability to track the sun. He also noticed that sunflowers prevented from moving were not as tough and leafy as those that were free to move. When plants were moved indoor with a settled overhead light, they continued to swing back and forth for a few days.
The indoor plants did start tracking the “sun” again when the apparent source of lighting was moved across the room. The plants could reliably tack the movement and return at night when the artificial day was close to a 24-hour cycle, but not when it was closer to 30 hours.
When sunflowers track the sun, the east sides of their stems grew more rapidly than the west sides. At night, the west sides grew faster as the stem swung the other way. The team identified a number of genes that were expressed at higher levels on the sunward side of the plant during the day or on the other side at night. A plant growth-regulating hormone (激素), called auxin, appears to be a key driver.
The “dance” to the sun cycle obviously slows when the sunflower matures (成熟) and its flowers open up. At that point, the plants stop moving during the day and settle down facing the sun in the east.
“Bees like warm flowers.” Harmer said, adding that the bees are cold-blooded, so landing on a warm flower saves them energy and perhaps feels really good.
“The morning warmth changes the flowers in a way to make them more appealing to insects, perhaps causing them to release more attractive scents earlier in the day.” he said “We’re currently testing this idea.”
1.Why did Harmer do the experiment on sunflowers?
A.To see how sunflowers grow up B.To show what sunflowers’ genes are.
C.To study why sunflowers track the sun. D.To check if sunflowers swing in cloudy days.
2.What does the underlined word “staking” probably mean in Paragraph 3?
A.breaking B.controlling C.growing D.searching
3.What is the result of sunflowers being stopped from moving?
A.They will produce a number of new genes. B.They will grow faster than usual.
C.They won’t swing back though set free. D.They won’t grow well.
An elderly carpenter (木匠) was ready to retire (退休). He told his boss that he planned to leave the building business and live a more relaxing life with his wife, enjoying his big family. He would miss the pay check each week, but he needed to retire. He believed they could get by (勉强过活) even on a small amount of money.
The boss was sorry to see his good worker leave and asked if he could build just one more house as a personal favor. The carpenter said yes, but soon afterwards he was found to be absent-minded. He used shoddy materials to build the house. How disappointing it was to end his career in this way!
When the carpenter finished all his work, the boss came to inspect (检查) the new house as usual. But after that, he handed the front-door key to the carpenter, saying. “This is your house, my gift to you.”
What a shock! What a shame! If he had known he was building his own house, he would have done it all so differently. Now he had to live in the worst house he had ever built in his life.
Think of yourself as the carpenter. Think about your house. Each day you hammer a nail, place a board, or put up a wall. Build wisely. It is the only life you ever build. Even if you live it for only one more day, that day deserves (值得) to be lived comfortably. Life is a do-it yourself project. Your life today is the result of your attitudes (态度) and choices in the past. Your life tomorrow will be the result of your attitudes and the choices you make today.
1.According to the article, the carpenter .
A.was too old to build a fine house B.had a large family to raise
C.was not in need of money D.was not welcome
2.The carpenter was when he learned that the house he had built was for himself.
A.excited B.delighted C.worried D.surprised
3.What does the writer mainly want to tell us in the text?
A.We should build a house wisely. B.Building a house is like building a life.
C.We should pursue (追求) a comfortable life. D.We should have the right attitude towards life.
Inventions make the world better, smarter and a little more fun.
| The folding bike helmet (头盔) People hate to wear a helmet because it’s thick and heavy. Morpher is a bike helmet made from plastics. It is just as strong as the traditional ones, but flexible (灵活的) enough to fold almost totally flat. Also it is much easier to carry. |
| Shoes that tie themselves After we see the movie Back to the Future, almost everyone wants a pair of self-tying shoes. Now, thanks to Nike, the shoes dream comes true. When you press a button, the shoes can tie themselves. |
| The smart alarm clock—Hello Sense An alarm clock, called Hello Sense, can improve your sleep. It can control the temperature, light and even air quality in your bedroom to help you have a perfect sleep environment. And it can record your sleep cycles. |
| Sweep potatoes that could save lives The lack (缺乏) of vitamin A can cause blindness and many other illnesses. In sub-Saharan Africa, plant experts are helping them grow a kind of new sweet potatoes. These potatoes can help them fight against some illnesses. |
1.Which company makes self-tying shoes?
A.Adidas. B.Kappa. C.Nike. D.Li-Ning.
2.The smart alarm clock can NOT .
A.improve our sleep B.record our sleep cycles
C.control our weight D.control the temperature in the bedroom
3.You can find the passage in a .
A.newspaper B.story book C.guide book D.cookery book
When I was a small boy, something happened to me that made me never put any wild creature in a cage.
We lived near a forest, and every evening the mockingbird would come and______. I decided to catch a young______and keep it in a cage, and in this way, I would have my own private musician. Then I succeeded in catching one and put it in a cage. At first, the bird was______, so it fluttered (扑腾) in the cage. But finally it was used to living in its new home. I felt very excited with myself and look forward to some beautiful singing.
On the second day, the little bird’s mother flew to the cage with______in her mouth. The baby bird ate everything. I was______to see this. Certainly the mother bird knew how to feed her baby better than I did.
The following morning when I went to see my bird, I found it______on the floor of the cage. I was terribly surprised and sad! What had happened?
Arthur Wayne, a famous biologist, happened to______my father at that time. After she knew my story, she explained to me, “A mother mockingbird, finding her young in a cage, will sometimes bring it poison berries. She thinks it better for her baby to die than to lose______.”
Since then I have never caught any living creature and put it in a cage. All living things have a right to live free.
1.A.dance B.fly C.sing D.jump
2.A.bird B.boy C.fish D.thief
3.A.happy B.careful C.active D.afraid
4.A.water B.food C.songs D.stones
5.A.worried B.pleased C.bored D.tired
6.A.alone B.alive C.dead D.sick
7.A.invite B.visit C.challenge D.introduce
8.A.friends B.parents C.freedom D.happiness
–I’m going to buy a car. Any advice, Charlie?
-- Well, it depends on ______. If money isn’t a problem, you can buy a BMW.
A.when will you buy one B.what color do you like
C.how much you can afford D.where you are driving
A baby's first month birthday is a special event in China and_____with a special party.
A.celebrates B.is celebrated C.was celebrated D.will celebrate
