A new study finds that plants communicate with one another to warn of danger.
We often consider plants as the furniture of the natural world. They don’t move; they don’t make sounds;they don’t seem to act on anything. But as is often the case, plants talk to each other all the time. And the language is a chemical (化学物质).
Over the years, scientists have reported that different types of plants, from trees to tomatoes, give out chemicals into the air to help neighbouring plants. These chemical warnings can spread information about one plant’s disease or infestation (虫害),so other plants can protect themselves. But how plants receive and act on the information exactly is still mysterious (神秘的).
In this week’s Science Magazine, researchers in Japan offered some explanations. They have found out one chemical message and traced it all the way from beginning to end.
The scientists looked at tomato plants infested by a common pest (害虫). To start out,they grew plants in two separate plastic spaces connected by a tube (管子). One plant was infested and placed upwind and the other was uninfested and placed downwind. The downwind plants were later exposed (暴露的)to the pest. The results showed that plants near sick neighbours before were able to protect themselves better against the pest.
They found one chemical appeared more often in the exposed plants. The chemical is called HexVic. The scientists discovered where HexVic came from, and put it over healthy plants. Those plants were then able to produce HexVic. Researchers made sure that uninfested plants could fight off bugs and diseases. How do they know when to protect themselves? They are warned first by their friendly plant neighbours.
It is not a simple story , and it may be happening in many other plants besides tomatoes. It may also be happening with more chemical signals that are still unknown to us. In a word, we know that plants not only communicate, but also look out for one another.
1.The underlined word “traced” in the fourth paragraph probably means _______here.
A. reported B. followed C. doubted D. developed
2.For scientists, which are the right steps to watch tomato plants infested by a pest?
① Place the infested plant upwind.
② Place the uninfested plant downwind.
③ Expose the downwind plants to the pest.
④ Grow plants in two separate plastic spaces connected by a tube.
A. ③①②④ B. ①④③②
C. ④①②③ D. ④②①③
3.You can put the sentence “The researchers also studied leaves from exposed plants and unexposed plants. " at the beginning of Paragraph ____.
A. 3 B. 4 C. 5 D. 6
4.Which of the following can be the best title of this passage?
A. Communicating Plants and Terrible Diseases
B. Talking Plants and Friendly Warnings
C. Protecting Plants and Clear Information
D. Growing Plants and Mysterious Chemicals
九年级英语阅读理解中等难度题
A new study finds that plants communicate with one another to warn of danger.
We often consider plants as the furniture of the natural world. They don’t move; they don’t make sounds;they don’t seem to act on anything. But as is often the case, plants talk to each other all the time. And the language is a chemical (化学物质).
Over the years, scientists have reported that different types of plants, from trees to tomatoes, give out chemicals into the air to help neighbouring plants. These chemical warnings can spread information about one plant’s disease or infestation (虫害),so other plants can protect themselves. But how plants receive and act on the information exactly is still mysterious (神秘的).
In this week’s Science Magazine, researchers in Japan offered some explanations. They have found out one chemical message and traced it all the way from beginning to end.
The scientists looked at tomato plants infested by a common pest (害虫). To start out,they grew plants in two separate plastic spaces connected by a tube (管子). One plant was infested and placed upwind and the other was uninfested and placed downwind. The downwind plants were later exposed (暴露的)to the pest. The results showed that plants near sick neighbours before were able to protect themselves better against the pest.
They found one chemical appeared more often in the exposed plants. The chemical is called HexVic. The scientists discovered where HexVic came from, and put it over healthy plants. Those plants were then able to produce HexVic. Researchers made sure that uninfested plants could fight off bugs and diseases. How do they know when to protect themselves? They are warned first by their friendly plant neighbours.
It is not a simple story , and it may be happening in many other plants besides tomatoes. It may also be happening with more chemical signals that are still unknown to us. In a word, we know that plants not only communicate, but also look out for one another.
1.The underlined word “traced” in the fourth paragraph probably means _______here.
A. reported B. followed C. doubted D. developed
2.For scientists, which are the right steps to watch tomato plants infested by a pest?
① Place the infested plant upwind.
② Place the uninfested plant downwind.
③ Expose the downwind plants to the pest.
④ Grow plants in two separate plastic spaces connected by a tube.
A. ③①②④ B. ①④③②
C. ④①②③ D. ④②①③
3.You can put the sentence “The researchers also studied leaves from exposed plants and unexposed plants. " at the beginning of Paragraph ____.
A. 3 B. 4 C. 5 D. 6
4.Which of the following can be the best title of this passage?
A. Communicating Plants and Terrible Diseases
B. Talking Plants and Friendly Warnings
C. Protecting Plants and Clear Information
D. Growing Plants and Mysterious Chemicals
九年级英语阅读理解中等难度题查看答案及解析
A new study finds that plants communicate with one another to warn of danger.
We often consider plants as the furniture of the natural world. They don’t move; they don’t make sounds, they don’t seem to act on anything. But as is often the case, plants talk to each other all the time. And the language is chemical.
Over the years, scientists have reported that different types of plants, from trees to tomatoes, give out chemicals into the air to help neighboring plants. These chemical warnings can spread information about one plant’s disease or infestation(虫害), so other plants can protect themselves. But how plants receive and act on many of the information exactly is still mysterious.
In this week’s Science Magazine, researchers in Japan offered some explanations. They have found out one chemical message and traced it all the way from beginning to end.
The scientists looked at tomato plants infested by a common pest(害虫). To start out, they grew plants in two separate plastic spaces connected by a tube(管子). One plant was infested and placed upwind and the other was uninfested and placed downwind. The downwind plants were later exposed(暴露) to the pest. The results showed that plants near sick neighbors before were able to protect themselves better against the pest.
They found one chemical appeared more often in the exposed plants. The chemical is called HexVic. The scientists discovered where HexVic come from, and put it over healthy plants. Those plants were then able to produce HexVic. Researchers made sure that uninfested plants could fight off bugs and diseases. How do they know when to protect themselves? They are warned first by their friendly plant neighbors.
It is not a simple story, and it may be happening in more plant species than tomatoes. It may also be happening with more chemical signals that are still unknown to us. In a word, we know that plants not only communicate, but also look out for one another.
1.The underlined “traced” in the fourth paragraph probably means _________ here.
A. reported B. followed C. doubted D. developed
2.For scientists, which are the right steps to watch tomato plants infested by a pest?
①Place the infested plant upwind.
②Place the uninfested plant downwind.
③Expose the downwind plants to the pest.
④Grow plants in two separate plastic spaces connected by a tube.
A. ③①②④ B. ③④①② C. ④①②③ D. ④③①②
3. You can put the sentence “The researches also studied leaves from exposed plants and unexposed plants.” At the beginning of ____________.
A. Paragraph 3 B. Paragraph 4 C. Paragraph 5 D. Paragraph 6
4.Which of the following can be the best title of this passage?
A. Communicating Plants and Terrible Diseases
B. Talking Plants and Friendly Warnings
C. Protecting Plants and Clear Information
D. Growing Plants and Mysterious Chemicals
九年级英语阅读理解中等难度题查看答案及解析
A new study finds that plants communicate with one another to warn of danger.
We often consider plants as the furniture of the natural world. They don’t move; they don’t make sounds, they don’t seem to act on anything. But as is often the case, plants talk to each other all the time. And the language is chemical.
Over the years, scientists have reported that different types of plants, from trees to tomatoes, give out chemicals into the air to help neighboring plants. These chemical warnings can spread information about one plant’s disease or infestation(虫害), so other plants can protect themselves. But how plants receive and act on many of the information exactly is still mysterious.
In this week’s Science Magazine, researchers in Japan offered some explanations. They have found out one chemical message and traced it all the way from beginning to end.
The scientists looked at tomato plants infested by a common pest(害虫). To start out, they grew plants in two separate plastic spaces connected by a tube(管子). One plant was infested and placed upwind and the other was uninfested and placed downwind. The downwind plants were later exposed(暴露) to the pest. The results showed that plants near sick neighbors before were able to protect themselves better against the pest.
They found one chemical appeared more often in the exposed plants. The chemical is called HexVic. The scientists discovered where HexVic come from, and put it over healthy plants. Those plants were then able to produce HexVic. Researchers made sure that uninfested plants could fight off bugs and diseases. How do they know when to protect themselves? They are warned first by their friendly plant neighbors.
It is not a simple story, and it may be happening in more plant species than tomatoes. It may also be happening with more chemical signals that are still unknown to us. In a word, we know that plants not only communicate, but also look out for one another.
1.The underlined “traced” in the fourth paragraph probably means _________ here.
A.reported B. followed
C. doubted D. developed
2.For scientists, which are the right steps to watch tomato plants infested by a pest?
① Place the infested plant upwind.
② Place the uninfested plant downwind.
③ Expose the downwind plants to the pest.
④ Grow plants in two separate plastic spaces connected by a tube.
A.③①②④ B. ①④③②
C. ④①②③ D. ④②①③
3.You can put the sentence “The researches also studied leaves from exposed plants and unexposed plants.” At the beginning of
A.Paragraph 3 B. Paragraph 4
C. Paragraph 5 D. Paragraph 6
4.Which of the following can be the best title of this passage?
A.Communicating Plants and Terrible Diseases
B.Talking Plants and Friendly Warnings
C.Protecting Plants and Clear Information
D.Growing Plants and Mysterious Chemicals
九年级英语阅读理解极难题查看答案及解析
David finds ______ difficult to communicate with his parents.
A. one B. it C. this D. that
九年级英语单选题困难题查看答案及解析
Sometimes parents find ______ hard to communicate with their children.
A. this B. that C. it D. one
九年级英语单项填空中等难度题查看答案及解析
I find _____ difficult to communicate with my parents. They never listen to me.
A. one B. it C. that
九年级英语单选题中等难度题查看答案及解析
David finds ___ difficult to communicate with his parents
A.one B.it C.this
九年级英语单选题中等难度题查看答案及解析
David finds ___ difficult to communicate with his parents
A.one B.it C.this
九年级英语单项填空中等难度题查看答案及解析
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.
九年级英语阅读单选中等难度题查看答案及解析
Recent studies have1. that exercise is good to 2. your physical strength and brain. A new study finds that people become 3. after starting a running program. In their study, the researchers had seven young people start a running program consisting of running 30minutes,two or three 4. a week for at least 12skills before and after the 3-month running program. After 12 weeks of running, scores on all of the tests5. greatly in the runners, as did their reaction times(反应时间)in completing the tests, but the scores began to fall again if the runners stopped their6..
The results could have suggestions for old people as 7..According to these researchers, old people8.started a 4-month exercise program also showed it may help doctors find a way to use exercise and running to help old people and those 9.Altheimer’s(老年痴呆) disease improve 10. memory and other mental skills.
九年级英语选词填空困难题查看答案及解析