Question: Too many cars have created a lot of serious problems in our world. Besides congestion , accidents and fast fuel consumption , cars are responsible for a good part of air pollution in big cities. All the time, they are pumping huge amounts of waste gases into the atmosphere. These gases are very harmful, causing disease and even death. Last winter, car fumes  formed heavy smog over Beijing, making the sky gloomy for weeks and deteriorating people's health. One possible solution is to design and develop clean cars and clean fuels. In Tsinghua University, campus buses are driven by electricity. In Beijing some of the public buses begin to run on natural gas, which does not give off as much carbon dioxide as the petrol. But it may take decades for the new models of clean cars to completely replace the traditional ones. Another solution is to develop modern public transportation systems and restrict  the use of private cars. If the price of petrol rises constantly and the public vehicles  are efficient and convenient enough, most people will not use private cars. And the total number of cars in big cities will reduce greatly. On the whole, the elimination  of air pollution needs the co-efforts from the government, the public and the environments. This problem will be solved only with the help of science and technology. What is the main reason for air pollution in big cities? A) congestion B) accidents C) fast fuel consumption D) cars
Answer: D

Question: Manhattan Island is surrounded on the east by the East and Harlem Rivers and on the west by the North and Hudson Rivers.It links with the other four towns which make up New York City and with New Jersey are by means of subways,underground tunnels and bridges which lead into Manhanttan from the surrounding area. The Brooklyn Bridge was the first suspension bridge to link Brooklyn to Manhanttan.It is also the second oldest bridge in New York.The architect was John Augustus Roebling,who was the chief engineer of the suspended Railroad Bridge at Niagara Falls. Misfortune accompanied the building of the bridge,which took place from 1869 to 1883.The architect died as a result of an accident early during the construction.His son,Washington Roebling,carried on his father's work,using the most advanced engineering techniques of the day.He also fell ill during the construction of the bridge and was obliged to direct the work on it from an apartment window overlooking the site. Since its construction the Brooklyn Bridge has remained a busy and important passage in New York. The Brooklyn Bridge is 6775 feet long and 1595 feet wide.The suspended part is 3450 feet long and 85 feet wide.It has a clearance of 133 feet above water level.Four huge cables extend across the bridge,supported by two towers,each 272 feet high.Each of these cables is made up of 5700 wires. In the course of the construction of the bridge  _  . A) the chief engineer was in short of money B) misfortune fell on the chief engineer C) John Augustus Roebling fell ill D) Washington Roebling met with an accident
Answer: B

Question: Peyton,an 11-year-old boy from Florida,has the enthusiasm of scientific invention and the-gift of Thomas Edison. The sixth-grader put his math and science skills as well as some real-life experience to use and created something that could benefit our world a lot ---- the sandless sandbag.Today he was named the winner of the Young Scientist Challenge for his sandbag. "I had a really terrifying experience with a hurricane," said Peyton."When I was 4,I experienced Hurricane Wilma.When it hit Florida in October 2005,my family and I crowded in a closet and watched the storm bring damage and death to our area,feeling terrible and hopeless." Saltwater flooding caused great damage,which made him think about how people can prepare for floods.Peyton,who has been solving math problems since he was 3,eventually came up with the sandless sandbag.     "Instead of filling it with sand,I filled it with just the right amount of chemicals and salt,"he said."What's amazing is that when you pick these bags up and they're not wet,they only weigh a pound or two." Unlike regular sandbags,Peyton's is light and easy to carry.They only expand when doused  with water.The bags are portable when dry and will not float away when wet. Experts praised his invention and said that the sandless sandbag could someday save a lot of lives and possessions."He understands the big picture.He thinks in terms of the influence on society and safety for the people around this area,"said Dr.Antonio,the engineering chairman at the University of Miami."We'd love to have him at our university." Peyton has to get through middle school and high school first,but until then,the young scientist will continue thinking and inventing. when the sandless sandbag is wet,it will   _  . A) be portable B) float away C) get heavy D) 1ose weight
Answer:
C