When a leafy plant is under attack,it doesn’t sit quietly.Back in 1983,two scientists,Jack Schultz and Ian Baldwin,reported that young maple trees getting bitten by insects send out a particular smell that neighboring plants can get.These chemicals come from the injured parts of the plant and seem to be an alarm.What the plants pump through the air is a mixture of chemicals known as volatile organic compounds,VOCs for short.
Scientists have found that all kinds of plants give out VOCs when being attacked.It’s a plant’s way of crying out.But is anyone listening?Apparently.Because we can watch the neighbors react.
Some plants pump out smelly chemicals to keep insects away.But others do double duty.They pump out perfumes designed to attract different insects who are natural enemies to the attackers.Once they arrive,the tables are turned.The attacker who was lunching now becomes lunch.考生如果怕自己錯過考試報名時間和考試時間的話，可以 免費預約短信提醒，屆時會以短信的方式提醒大家報名和考試時間。
In study after study,it appears that these chemical conversations help the neighbors.The damage is usually more serious on the first plant,but the neighbors,relatively speaking,stay safer because they heard the alarm and knew what to do.
Does this mean that plants talk to each other?Scientists don’t know.Maybe the first plant just made a cry of pain or was sending a message to its own branches,and so,in effect,was talking to itself.Perhaps the neighbors just happened to “overhear” the cry.So information was exchanged,but it wasn’t a true,intentional back and forth.
Charles Darwin,over 150 years ago,imagined a world far busier,noisier and more intimate(親密的) than the world we can see and hear.Our senses are weak.There’s a whole lot going on.
1.What does a plant do when it is under attack?
A.It makes noises.
B.It gets help from other plants.
C.It stands quietly.
D.It sends out certain chemicals.
2.What does the author mean by “the tables are turned” in paragraph 3?
A.The attackers get attacked.
B.The insects gather under the table.
C.The plants get ready to fight back.
D.The perfumes attract natural enemies.
3.Scientists find from their studies that plants can .
A.predict natural disasters
B.protect themselves against insects
C.talk to one another intentionally
D.help their neighbors when necessary
4.What can we infer from the last paragraph?
A.The world is changing faster than ever.
B.People have stronger senses than before.
C.The world is more complex than it seems.
D.People in Darwin’s time were more imaginative.
Benjamin West,the father of American painting,showed his talent for art when he was only six years of age.But he did not know about brushes before a visitor told him he needed one.In those days,a brush was made from camel’s hair.There were no camels nearby.Benjamin decided that cat hair would work instead.He cut some fur from the family cat to make a brush.
The brush did not last long.Soon Benjamin needed more fur.Before long,the cat began to look ragged(蓬亂).His father said that the cat must be sick.Benjamin was forced to admit what he had been doing.
The cat’s lot was about to improve.That year,one of Benjamin’s cousins,Mr.Pennington,came to visit.He was impressed with Benjamin’s drawings.When he went home,he sent Benjamin a box of paint and some brushes.He also sent six engravings(版畫) by an artist.These were the first pictures and first real paint and brushes Benjamin had ever seen.
In 1747,when Benjamin was nine years old,Mr.Pennington returned for another visit.He was amazed at what Benjamin had done with his gift.He asked Benjamin’s parents if he might take the boy back to Philadelphia for a visit.
In the city,Mr.Pennington gave Benjamin materials for creating oil paintings.The boy began a landscape(風景) painting.William Williams,a well-known painter,came to see him work.Williams was impressed with Benjamin and gave him two classic books on painting to take home.The books were long and dull.Benjamin could read only a little,having been a poor student.But he later said,“Those two books were my companions by day,and under my pillow at night.”While it is likely that he understood very little of the books,they were his introduction to classical paintings.The nine-year-old boy decided then that he would be an artist.
1.What is the text mainly about?
A.Benjamin’s visit to Philadelphia.
B.Williams’ influence on Benjamin.
C.The beginning of Benjamin’s life as an artist.
D.The friendship between Benjamin and Pennington.
2.What does the underlined sentence in paragraph 3 suggest?
A.The cat would be closely watched.
B.The cat would get some medical care.
C.Benjamin would leave his home shortly.
D.Benjamin would have real brushes soon.
3.What did Pennington do to help Benjamin develop his talent?
A.He took him to see painting exhibitions.
B.He provided him with painting materials.
C.He sent him to a school in Philadelphia.
D.He taught him how to make engravings.
4.Williams’ two books helped Benjamin to .
A.master the use of paints
B.appreciate landscape paintings
C.get to know other painters
D.make up his mind to be a painter