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Before a new type airplane goes service, every part of it is tested again and again. But there are two tests that are more of into important than the others.
The first is called the “tank test”. A modern airplane must fly very high in the sky. Air must be pumped into the plane so that the passengers can breathe. The metal structure of the plane has to be very strong for this reason. When the plane is filled with air, the air presses against the skin of the plane inside. The pressure(压力)on a small window is like a huge foot that is trying to get out. If a small part of the plane were to fail, the plane would explode in the sky. To test the structure of the plane, the plane is lowered into a huge tank or container of water. Then it is filled with air. The pressure inside the plane is greater than it ever will be when it is high up in the air. Finally, there is an explosion. This does not cause so much damage inside the water tank as it would anywhere else. Engineers can discover which part of the plane has broken. Then that part is made stronger.
The most dangerous test happens when the new plane is going through test flights in the air. The test must find out exactly what happens when the engines(发动机) are all shut off at once. The plane begins to fall like a stone. It is the pilot’s job to find out how he can get control of the plane again. These two tests are examples of how planes are made safe before they ever carry passengers.
By doing the “tank test”, the engineers can find out ____.
A. the amount of air in the plane B. the strength of the plane structure
C. the pressure inside and outside the plane D. the power of the airplane engines
What will happen to the plane under the “tank test”?
A. It will be broken B. It will be made stronger.
C. It will be filled with water. D. It will be tested by pilots.
According to the text, why are test flights most dangerous?
A. The plane may explode in the air B. The pilot may lose control of the plane.
C. The engines may be damaged. D. Too much air may get into the plane.
What might be the most suitable title for the text?
A. Two Important Tests on Airplane B. The Importance of Flying Safety
C. The Danger of Testing Airplanes D. How Airplanes Are made and Tested
查看习题详情和答案>>A "lost tribe" that reached America from Australia may have been the first Native Americans, according to a new theory.
If proved by DNA evidence, the theory will break long established beliefs about the southerly migration of people who entered America across the Bering Strait, found it empty and occupied it.
On this theory rests the belief of Native Americans to have been the first true Americans. They would be classified to the ranks of escapee, beaten to the New World by Aboriginals (土著人) in boats.
To a European, this may seem like an academic argument, but to Americans it is a philosophical question about identity (身份), Silvia Gonzales, of Liverpool University said .
Her claims are based on skeletons found in the California Peninsula of Mexico that have skulls (头骨) quite unlike the broad Mongolian features of Native Americans. These narrow-skulled people have more in common with southern Asians, Aboriginal Australians and people of the South Pacific Region.
The bones, stored at the National Museum of Anthropology (人类学) in Mexico City, have been carbon-dated and one is 12,700 years old, which places it several thousand years before the arrival of people from the North. "We think there were several migration waves into the Americas at different times by different human groups," Dr. Gonzales said． "The timing, route and point of origin of the first colonization of the Americas remains a most contentious topic in human evolution."
But comparisons based on skull shape are not considered conclusive by anthropologists, so a team of Mexican and British scientists, backed by the Natural Environment Research Council, has also attempted to take out DNA from the bones. Dr. Gonzales declined yesterday to say exactly what the results were, as they need to be checked, but indicated that they were consistent（一致） with an Australian origin.
It is generally considered that the first Native Americans came from _____.
A．North Asia B．Australia C．South Pacific D．South Asia
The skeletons found in the California Peninsula of Mexico have _____.
A．the broad skull shape
B．the narrow skull shape
C．different features of Aboriginal Australians
D．the same features of Native Americans
The underlined “contentious” is similar in meaning to “_____”.
A．likely to cause great interest B．difficult to solve
C．well-known to all D． likely to cause argument
Which of the following statements is true according to the text?
A．Research on skulls can draw an exact conclusion.
B．DNA tests have proved the fact that the first Native Americans came from Australian.
C．Scientists are still not sure about the origin of the Native Americans.
D．People began to enter America across the Bering Strait about 12,700 years ago.
查看习题详情和答案>>A university graduate described as a “respectable and intelligent” woman is seeking professional help after being convicted of （证明有……罪）shoplifting for the second time in six months．
Ana Luz, recently studying for her PhD, has been told she could end up behind bars unless she can control the desire to steal from shops．
Luz ,who lives with her partner in Fitzwilliam Road ,Cambridge ,admitted stealing clothes worth ￡9．95 from John Lewis in Oxford Street ,London ,on March 9．
Phillip Lemoyne ,prosecuting（起诉）,said Luz selected some clothes from a display and took them to the ladies’ toilet in the store．When she came out again she was wearing one of the skirts she had selected ,having taken off the anti-theft security alarms（防盗警报装置）．
She was stopped and caught after leaving the store without paying ,Mr Lemoyne said．
He added that she was upset on her arrest and apologized for her actions．
Luz,28, was said to have been convicted of shoplifting by Cambridge judges last October ,but Morag Duff, defending ,said she had never been in trouble with the police before that．
“She is ashamed and embarrassed but doesn’t really have any explanation why she did this ,” Miss Duff said．“She didn’t intend to steal when she went into the store．She is at a loss to explain it．She is otherwise a very respectable and intelligent young lady．She went to her doctor and asked for advice because she wants to know if there is anything in particular that caused her to do this．”
Judge David Azan fined Luz ￡ 50, and warned : “You’ve got a criminal record．If you carry on like this ,you will end up in prison ,which will ruin your bright future you may have．”
Luz achieved a degree in design at university in her native Spain ,went on to a famous university in Berlin , Germany for her master’s degree and is now studying for a PhD at Cambridge University ,UK．
What is Ana Luz’s nationality?
A．American． B．British． C．Spanish． D．German．
What does the underlined sentence “She is at a loss to explain it” mean?
A．In her opinion it was a loss to the clothes shops where she stole things．
B．She doesn’t have any idea why she has the desire to steal from shops．
C．She thinks it is a loss for her to explain why she stole things from shops．
D．Personally she feels ashamed and embarrassed for her shoplifting actions．
Which of the following best explains the meaning of the word “shoplifting” used in the passage?
A．Carrying goods in a lift for a shop．
B．Taking goods to the ladies’ toilet．
C．Selecting some goods from a display．
D．Taking goods from a shop without paying．
From the passage we can learn that ．
A．Ana Luz is already got her PhD at Cambridge University ,UK
B．Ana Luz is ashamed and embarrassed and knows why she often did so
C．the university graduate will be put in prison if she steals in shops once more
D．Phillip Lemoyne is the “respectable and intelligent” woman’s defense lawyer
查看习题详情和答案>>Like most people, I was brought up to look upon life as a process of getting. It was not until in my late thirties that I made this important 36 : giving-away makes life so much more exciting. You need not worry if you 37 money.
This is how I 38 with giving-away. If an idea for improving the window display of a neighborhood store 39 to me, I step in and make the suggestion to the 40 . If an accident takes place, the 41 of which I think the local police could use, I 42 him up and tell him about it, though I am not in 43 here. One discovery I made about this world is to give 44 getting something back, though the 45 often comes in an unexpected form.
One Sunday morning the local post office delivered an important 46 letter to my home, though it was 47 to me at my office. I wrote the postmaster a note of 48 . More than a year later I needed a post-office box for a new business I was 49 . I was told at the window that there were 50 boxes left, and that my name would have to go on a long 51 list. As I was about to 52 , the postmaster appeared in the 53 .“Wasn’t it you that wrote us that letter a year ago about delivering a special delivery to your home?” I said it was. “Well, you certainly are going to have a box in this post office 54 we make one for you. You don’t know what a letter like that means to us. We usually get 55 but complaints（投诉）.”
36．A．decision B．research C．speech D．discovery
37．A．earn B．lack C．spend D．steal
38．A．experienced B．connected C．combined D．agreed
39．A．happens B．flashes C．sticks D．leads
40．A．postmaster B．headmaster C．storekeeper D．policeman
41．A．story B．damage C．challenge D．material
42．A．call B．hold C．break D．pick
43．A．need B．trouble C．common D．charge
44．A．within B．without C．for D．before
45．A．process B．goal C．return D．concern
46．A．curious B．immediate C．special D．heavy
47．A．realized B．addressed C．forgotten D．brought
48．A．invitation B．apology C．instruction D．appreciation
49．A．dealing B．providing C．operating D．starting
50．A．enough B．some C．no D．more
51．A．admitting B．relating C．examining D．waiting
52．A．leave B．shout C．guess D．conduct
53．A．window B．doorway C．library D．yard
54．A．in case B．now that C．even if D．as if
55．A．anything B．everything C．nothing D．something
查看习题详情和答案>>Like most people, I was brought up to look upon life as a process of getting. It was not until in my late thirties that I made this important 36 : giving-away makes life so much more exciting. You need not worry if you 37 money.
This is how I 38 with giving-away. If an idea for improving the window display of a neighborhood store 39 to me, I step in and make the suggestion to the 40 . If an accident takes place, the 41 of which I think the local police could use, I 42 him up and tell him about it, though I am not in 43 here. One discovery I made about this world is to give 44 getting something back, though the 45 often comes in an unexpected form.
One Sunday morning the local post office delivered an important 46 letter to my home, though it was 47 to me at my office. I wrote the postmaster a note of 48 . More than a year later I needed a post-office box for a new business I was 49 . I was told at the window that there were 50 boxes left, and that my name would have to go on a long 51 list. As I was about to 52 , the postmaster appeared in the 53 .“Wasn’t it you that wrote us that letter a year ago about delivering a special delivery to your home?” I said it was. “Well, you certainly are going to have a box in this post office 54 we make one for you. You don’t know what a letter like that means to us. We usually get 55 but complaints（投诉）.”
36．A．decision B．research C．speech D．discovery
37．A．earn B．lack C．spend D．steal
38．A．experienced B．connected C．combined D．agreed
39．A．happens B．flashes C．sticks D．leads
40．A．postmaster B．headmaster C．storekeeper D．policeman
41．A．story B．damage C．challenge D．material
42．A．call B．hold C．break D．pick
43．A．need B．trouble C．common D．charge
44．A．within B．without C．for D．before
45．A．process B．goal C．return D．concern
46．A．curious B．immediate C．special D．heavy
47．A．realized B．addressed C．forgotten D．brought
48．A．invitation B．apology C．instruction D．appreciation
49．A．dealing B．providing C．operating D．starting
50．A．enough B．some C．no D．more
51．A．admitting B．relating C．examining D．waiting
52．A．leave B．shout C．guess D．conduct
53．A．window B．doorway C．library D．yard
54．A．in case B．now that C．even if D．as if
55．A．anything B．everything C．nothing D．something
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