阅读下面短文，把A—D四个句子填入文中空缺处，使短文内容完整、正确，然后完成第75小题。     Gasoline (汽油) prices are getting higher and higher. The price make it hard for drivers to afford the fuel (燃料).

      71________ The new cars are different and they can run on many different kinds of fuels. Some of these cars are called “hybrids”. One kind of these cars can run on a special fuel, filled with a gas called hydrogen (氢气). 72________ They give off no emissions (排放物) when they run on the roads, so they are very clean and good for the environment.

One car makers is excited about hydrogen fuel cell technology. 73________ Once we use the oil up, it will take millions of years for more oil to form. Since gasoline is made from oil, that could be a problem for drivers and companies if they still drive or make traditional cars. 74________

People are testing buses with hydrogen fuel cells and we may see this kind of buses on the roads in the near future.

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75. What is the main idea of the passage?

   A. Gasoline is becoming more and more expensive.

   B. Traditional cars polluted the environment badly.

   C. The special fuel cell is not only useful, but also cheap.

   D. Some new kinds of cars will take the place of the traditional ones.

　　 Gasoline (汽油) prices are getting higher and higher. The price makes it hard for drivers to afford the fuel (燃料).

　　 81_______ The new cars are different and they can run on many different kinds of fuels. Some of these cars are called "hybrids". One kind of these cars can run on a special fuel, filled with a gas called hydrogen (氧气). 82______ They give off no emissions (排放物) when they run on the roads, so they are very clean and good for the environment.

　 One car maker is excited about hydrogen fuel cell technology. 83_____ 　Once we use the oil up, it will take millions of years for more oil to form. Since gasoline is made from oil, that could be a problem for drivers and companies if they still drive or make traditional cars. 84_______

People are testing buses with hydrogen fuel ceils and we may see this kind of buses on the roads in the near future.

(　 )85. What is the main idea of the passage?

　　 A. Gasoline is becoming more and more expensive.

　　 B. Traditional cars polluted the environment badly.

　　 C. The special fuel cell is not only useful, but also cheap.

　　 D. Some new kinds of cars will take the place of the traditional ones.

We sometimes call the lion “the king of the jungle (丛林)” because it is stronger and more dangerous than other animals. It can run faster than many animals and it can hunt (捕猎) the best. It is the highest animal in the   1  food chain (食物链).
In the sea, the shark is one of the animals at the  2  of the food chain. It can swim faster than most other sea animals, and it can use its big teeth to eat them.
What is at the top of the world’s food chain?  3  are! We are not the biggest or fastest, but we are the   4  We could not run faster than cheetahs (猎豹),  so we  5  cars and now we can move the fastest. We could not  6  better than lions, so we invented guns (枪). Now we can hunt the best.
People’s inventions are clever, but they can be dangerous, too. For example, people invented  7 , and now they make the air and rivers dirty. This can make   8  changes. Dirty rivers kill fish.  Then bears cannot eat the fish and the bears die. If we kill one part of the food chain,   9  also die. Remember that we are a part of the food chain, so we are in danger too! If we protect animals, we are protecting   10 ! We should and we could do something for the world!