题目
题型：同步题难度：来源：
is tested again and again. But there are two tests that are more
important than all 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(结构) 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 pilot 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.
B. the strength of the plane structure
C. the pressure inside and outside the plane
D. the power of the airplane engines
B. It will be made stronger.
C. It will be filled with water.
D. It will be tested by pilots.
B. The pilot may lose control of the plane.
C. The engines may be damaged.
D. Too much air may get into the plane.
B. The Importance of Flying Safely.
C. The Danger of Testing Airplanes.
D. How Airplanes Are Made and Tested.
答案
核心考点
试题【阅读理解。 Before a new type of airplane goes into service,every part of itis tes】；主要考察你对题材分类等知识点的理解。[详细]
举一反三
long missions on the International Space Station(ISS). ISS crewmembers usually live in space for at
least a quarter of a year. They work five days on and two days off to mimic the normal way they do things on Earth as much as possible . Weekends give the crew valuable. Weekends give the crew valuable time
to rest and do a few hours of housework. They can communicate with family and friends by email ,
internet phone and through
Private video conferees.
While astronauts cannot go to a baseball game or a movie in orbit, there are many familiar active tics
that they can still enjoy . Before a mission. The family and friends of each ISS crewmember put together
a collection of family photos, messages, videos and reading material for
The astronauts to look at when they will be floating 370 kilometers above the Earth. During their mission,
the crew also receives care packages with CDs, books, magazines, photos and letters . And as from early 2010, the internet became available on the ISS , giving astronauts the chance to do some "web surfing (冲浪)"in their personal time. Besides relaxing with these more common entertainments, astronauts can
simply enjoy the experience of living in space.
Many astronauts say that one of the most relaxing things to do in space is to look out the window and
stare at the universe and the Earth"s vast land mass and oceans.
B. Copy
C. Change
D. Lose
B. The are impatient and annoyed
C. The are impatient and ammoyed.
D. The are excited and curious.
B. find living in space a bit boring and tiring
C. regard space life as common
D. love to see the Earth from space
B. connect with people on the Earth
C. observe the Earth from space
D. spend their free time in space
aspirin had a reduced death rate ,especially from heart disease.
The research,based on data from a major trial that has tracked almost 80,000 women since 1976,
found that women who reported using aspirin on a regular basis had a 25 percent lower risk of death
from any cause than women who didn"t take the drug.
The risk of death from cardiovascular (心血管的) disease was 38 percent lower for aspirin users,
and there was also a 12 percent reduction in cancer deaths that took effect after a decade of aspirin
use, the researchers found in their report based on the Nurses" Health Study.
However,an accompanying editorial in the journal cautioned that the results were open to debate
and far from definitive.
The dissenting (持异议的) editorial was based on results of an earlier trial by the Women"s Health
Study, which followed almost 40,000 women for 11 years and found no reduction in overall deaths.
Therefore,the new findings" cannot overcome the accumulated evidence that aspirin is not particularly
effective for the primary prevention of death from cardiovascular disease in women. "
" This is a complicated issue , " said Dr. Andrew T. Chan, leading author of the new report. "We
understand that aspirin has potential health benefits,but who would aspirin therapy(疗法) be appropriate
for? There are areas of disagreements that need further study before that question can be answered" ,
Chan said. But there is information from the two large studies and other trials that can help guide women
and their physicians,he said. And anyone who is thinking about daily aspirin should really talk with doctors about the benefits and risks.
B. cancer
C. lose of memory
D. aspirin side effects
B. Which of the two researches is really reliable?
C. Who will do the further study in this area?
D. Who are proper for this treatment?
B. The earlier one.
C. Neither.
D. Both.
B. start immediately with the help of their physicians
C. concentrate on the benefits instead of the risks
D. turn to their physicians for only the benefit it has
B. To introduce two controversial researches.
C. To draw a final conclusion on the debate.
D. To help women live longer and healthier.
full super-conducting experimental nuclear fusion (核聚变) device known as"artificial sun"in the world,
which will produce energy like the sun.
It is reported that this device consists of five layers of components(成分)from inside to outside and the
circulating magnet container in the innermost layer looks like a giant" swim ring". In experimental tests,the
temperature of inner" swim ring" will reach as high as 100 million degrees Celsius. Therefore,such
component is a significant part to stimulate solar fusion reactions.
Wan Yuanxi,who is in charge of the project called Experimental Advanced Super-conducting
Tokamak( EAST) ,an important scientific project under China"s ninth five-ycar plan,explained the reason
why the sun always gives off light and why the energy it produces will not decrease. Under high pressure
and high temperature, fusion reactions will take place from inside to outside of the sun.
Such fusion reactions will give rise to a great deal of energy to enable the sun to continuously emit light
and heat. However,fusion reactions on the sun are uncontrollable,just like an H-bomb explosion seen on
the earth. A huge amount of energy will be produced in a minute,which may be destructive. In order to
make use of such energy,a transformation from the process of energy production to a stable,sustainable
and controllable process is needed. EAST is serving to initiate such a transformation. Under magnetic
force,the op-
eration of hydrogen plasma isotope (同位素) will be restrained in the" swim ring" and high density
collision will happen, namely the fusion reactions. The hydrogen isotope got from one liter of seawater
can produce energy equal to 300 liters of gasoline through complete fusion reactions.
Wan said that we can get endless clean energy by producing such a device for accomplishing fusion
reactions,which is equal to one or a few small suns made by human beings themselves so that they can
ceaselessly obtain energy from nuclear fusions.
B. The Sun and the" Artificial Sun".
C. How to Produce the" Artificial Sun".
D. China Built the World"s First"Artificial Sun".
B. Man-made.
C. Actual.
D. Ancient.
B. EAST is an important scientific project under China"s ninth five-year plan.
C. Such fusion reactions in the" artificial sun" will give us limited energy.
D. The hydrogen isotope got from one liter of seawater can produce energy equal
to 300 liters of gasoline through complete fusion reactions.
B. To get more light.
C. To have the sun shining for us in 24 hours
D. To study the inside of the real sun.
Call on a Ladybug
There are lots of insects that farmers hate. But there also are some they like. These protect crops
against damage from other insects. A good example is the lady beetle,also known as the ladybug
Lady beetles are a natural control for aphids (蚜虫). Lady beetles are red,orange or black. They
often have black spots,though some have light colored spots. Different kinds of lady beetles have
different numbers of spots. There are lady beetles with four,five, seven and fourteen spots.
Many of the well-known kinds of lady beetles come from Asia or Europe. They are now common
throughout the United States.
American scientists imported one kind of lady beetle,the multicolored Asian lady beetle,as early as
1916. They released them as an attempt to control some kinds of insects. Over the years,the beetle has
become established,possibly helped by some that arrived with imported plants on ships.
Experts say over 450 kinds of lady beetles are found in North America. Some are native to the area. Others have been brought from other places. Almost all are helpful to farmers.
The Asian lady beetles now in the United States probably came from Japan. The Asian lady beetle
eats aphids that damage crops like soybeans,fruits and berries.
In the southern United States,Asian lady beetles have reduced the need for farmers to use pest-killing
poisons on pecan trees. This popular tree nut suffers from aphids and other pests that the
beetles eat.
But some people say the Asian lady beetle has itself become a pest. They worry that the beetles may
eat their late-autumn fruit crops.
Experts say Asian lady beetles may appear in large numbers in some years. But they say the insects
are too helpful to be considered pests.
B. Most of them are red,orange and black.
C. They each have the same number of spots on them.
D. The farms like them.
B. hundreds of years
C. half a century
D. a century
B. Only some imported ladybugs are helpful to the local plants.
C. Soybeans,fruits and berries are favorites of Aphids.
D. Pecan trees are common in the south of America.
B. more pests than helpful insects.
C. helpful as well as destructive.
D. are more destructive than helpful.
(啮齿动物) in its network of tunnels and burrows (穴). But it was not crowded in this town. There was
sunlight and fresh air for all. There was enough grass to furnish food.
Scientists have leamed that the prairie dogs found in many parts of the West can live together in huge
numbers without being crowded. Scientists know that each prairie dog town is divided into separate
territories. Each section belongs to a family group,or clan.
The animals cooperate in many ways. One of the prairie dogs who sense danger will wam the others. All the animals take cover. Still,the animals stay within their own sections of the town and eat only the
plants that grow there. Young prairie dogs are taught the clan boundaries,and they later teach the
boundaries to their own young.
What happens when one clan becomes too large for the food in its territory? Is there any war with
the next-door clan to win more land? Not at all. The territory is turned over to the younger members
of the clan. The older animals move out to the edge of the town. They stake out a new territory and dig
a new network of tunnels. Before long, another clan will form a new territory beyond them. In this way,
a prairie dog town grows and grows,but the number of animals in each section stays about the same.
B. provide
C. cook
D. furniture
B. They live in a crowded and cooperative family.
C. They live in a big but united family.
D. They live in a large family without cooperation.
B. young prairie dogs must find a new territory
C. young prairie dogs should fight to gain more land
D. young prairie dogs shouldn"t get food from other territories
the one that___．
B. the older animals move out of the town when they become too large for the food
C. prairie dogs build the network of tunnels and burrows to form a territory in the town
D. there was sunlight,fresh air and enough grass for all
最新试题
- 1史书记载说汉武帝“有亡秦之失而免于亡秦之祸”，你怎么看？你认为汉武帝是怎样的一位封建皇帝？_______________
- 2阅读下面的材料，完成题目。（6分）张清是华南理工大学建筑学院2010级的学生，为实现“远行”的梦想，大学期间，他一直靠打
- 3如图所示是开瓶时使用的开瓶器（图a），使用时相当于一个_______杠杆（选填：“省力”、“费力”或“等臂”）。图b所示
- 4如图所示，水平地面M点左侧粗糙，右侧光滑．整个空间有一场强大小E1=1×103N/C、方向竖直向下的匀强电场．质量mA=
- 5（B类题）一小船与船上人的总质量为160kg，以2m/s的速度匀速向东行驶，船上一个质量为60kg的人，以6m/s的水平
- 6关于匀变速直线运动的说法，正确的是( )A．它一定是速度越来越大的直线运动B．它是加速度越来越大的直线运动C．它是加
- 7如图甲所示，竖直平面内的光滑轨道由倾斜直轨道AB和圆轨道BCD组成，AB和BCD相切于B点，CD连线是圆轨道竖直方向的直
- 8某校举行中学生“日常生活小常识”知识比赛,比赛分为初赛和复赛两部分，初赛采用选手从备选题中选一题答一题的方式进行；每位选
- 9一块完整的骨（如肱骨）属于（ ）A．细胞B．组织C．器官D．系统
- 10Do you know of anyone who uses the truth to deceive (欺骗)? Wh
热门考点
- 1下列有关人体水分调节的叙述，正确的是[ ]A．大量饮水，则抗利尿激素分泌增加B．渴觉中枢兴奋，则抗利尿激素分泌减
- 2一条长为10厘米的线段两端分别在一个直二面角的两个平面内，且与二面角的两个面所成角的正弦值分别为35和12，则这条线段在
- 3When delivering the speech, you can _________your note if ne
- 4小芸同学想利用一台已经调好的天平、一只空杯和适量的水，测量妈妈刚买回来的面粉的密度，她的操作步骤如下，请填写出正确的操作
- 5老子和孔子是先秦时期的两位先哲，虽属不同的学派，但二者在思想上却有相似之处，主要表现在 [ ]A．治国的理念上
- 6Fred entered without knocking and, very out of breath, sank
- 7如图是我市某景点6月份1～10日每天的最高温度折线统计图．由图中信息可知该景点这10天最高温度的中位数是 （ ）℃
- 8若﹣1＜a＜b＜0，则下列式子中正确的是[ ]A．﹣a＜﹣bB．C．|a|＜|b|D．a2＞b2
- 9面对国际金融危机的冲击，从2008年第四季度以来，我国实施了积极的财政政策和适度宽松的货币政策，较快扭转了经济增速下滑的
- 10下列各项中标点符号使用正确的一项是A．吃空晌就是人死了，工资或离退休费照拿；工作人员被开除了，仍在原单位领取工资和津贴；