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A．By sending water directly back to the sea with great force.
B．By reducing wave energy.
C．By reducing beach width.
D．By stabilizing beachfront construction.
答案
更多“A．By sending water directly back to the sea with great force.B．By reducing wave energy”相关的问题
第1题
A．By e-mail.
B．By sending her fax.
C．By calling her.
D．By visiting her.
第2题
A.By ordering them.
B.By paying the money now,
C.By calling the clerk.
D.By sending an e-mail.
第3题
How did Fairfax County police identify the teenagers as gang members？
A．By investigating the students recruited.
B．By sending a policeman to spy on the gang.
C．By watching the spot they meet regularly.
D．By checking their self-descriptions online.
第4题
A．By filtering sea water.
B．By treating sea water with chemicals.
C．By taking salt out of sea water.
D．By drying up sea water.
第5题
A．By good sense of water waves made by quarries.
B．By good sense of smell and electrical and magnetic power.
C．By good sense of light.
D．By good sense of blood.
第6题
The greatest part of necessary funds is raised by taxes. A tax is money that we all must pay to support the government. The law orders us to pay taxes. We have no choice in the matter. Almost everyone pays some taxes in one form. or another.
(30)
A．By taxing public services.
B．By providing needed services.
C．By making people pay for private bills.
D．By collecting taxes.
第7题
听力原文： We know that we have to pay for what we get. If we buy food, We know there will be a bill to pay. These are private bills. But there are also public bills that must be paid. Public bills are paid by the government. In turn we get these services through taxes. What would happen if everyone in the city stopped paying taxes？ The water supply would stop; water might become unclean and impure. The streets might not be cleaned. There would be no police force to protect people and property. Schools would be closed. People would become sick and diseases might spread. We should not want to live in such a city. We all want pure water and food, clean streets and good schools. We want the police to prevent crime. The chief duty for every government is to protect persons and property. More than three quarters of the money spent by our government is used for this purpose. The next largest amount of public money goes to teach and train our citizens. Billions of dollars each year are spent on schools and libraries. Public money is used to pay the teachers and all the public officials. A large number of public funds are also spent on roads.
The greatest part of necessary funds is raised by taxes. A tax is money that we all must pay to support the government. The law orders us to pay taxes. We have no choice in the matter. Almost everyone pays some taxes in one form. or another.
(26)
A．By taxing public services.
B．By making people pay for private bills.
C．By providing needed services.
D．By collecting taxes.
第8题
听力原文： The idea of fighting a noise by making more noise sounds strange, but that's exactly what motor engineers are doing in Germany and some other countries.
Carmaker's research and development laboratories have already proved that mixing in more noise with the help of loudspeakers can reduce the unwanted noise.
Physicists have known about the technique for a long time. Sound is made up of pressure waves in the air. If two sound waves of the same frequency mix so that the highest point of one wave happens at the same time with the lowest point of the other wave, the result is no sound. Therefore, by producing a perfect copy of the noise and delaying it by half a wave cycle, we can kill the unwanted noise. Using this technique many carmakers are racing to develop noise-killing systems both inside and outside the cars.
Another good thing about the use of noise-killing systems is that it saves the need for a silencer, which not only reduces the weight of a car, but also makes the motor burn less oil and work better.
Some engineers believe that the noise-killing system will be used in most cars in 1996. But the carmakers haven't decided if they will put it into production because it would add several hundred dollars to the cost of their cars.
(30)
A．By mixing high frequency sound waves with low frequency sound waves.
B．By producing pressure waves going in the opposite direction.
C．By mixing new sound waves with the noise and sending them out together.
D．By making copies of the unwanted sound waves and letting them out a little later.
第9题
Although their missions blended commercial and political-military imperatives, the explorers involved all accomplished some significant science simply by going where no scientists had gone before.
Today Mars looms（隐约出现）as humanity’s next great terra incognita（未探明之地）. And with doubtful prospects for a short-term financial return, with the cold war a rapidly fading memory and amid a growing emphasis on international cooperation in large space ventures, it is clear that imperatives other than profits or nationalism will have to compel human beings to leave their tracks on the planet’s reddish surface. Could it be that science, which has long played a minor role in exploration, is at last destined to take a leading role？ The question naturally invites a couple of others: Are there experiments that only humans could do on Mars？ Could those experiments provide insights profound enough to justify the expense of sending people across interplanetary space？
With Mars the scientific stakes are arguably higher than they have ever been. The issue of whether life ever existed on the planet, and whether it persists to this day, has been highlighted by mounting evidence that the Red Planet once had abundant stable, liquid water and by the continuing controversy over suggestions that bacterial fossils rode to Earth on a meteorite（陨石）from valuable data about the range of conditions under which a planet can generate the complex chemistry that leads to life. If it could be established that life arose independently on Mars and Earth, the finding would provide the first concrete clues in one of the deepest mysteries in all of science: the prevalence of life in the universe.
第36题：According to the passage, the chief purpose of explorers in going to unknown places in the past was ________.
A) to display their country’s military might
B) to accomplish some significant science
C) to find new areas for colonization
D) to pursue commercial and state interests
第10题
What is the main goal of sending human missions to Mars？
A) To find out if life ever existed there.
B) To see if humans could survive there.
C) To prove the feasibility of large-scale space ventures.
D) To show the leading role of science in space exploration.
