How do you store and transport the hydrogen?
Hydrogen is a large gas of its kind, and it is not nearly as easy to work with as gasoline. Compressing the gas requires energy, and compressed hydrogen contains far less energy than the same volume of gasoline. However, solutions to the hydrogen storage problem are surfacing.
For example, hydrogen can be stored in a solid form in a chemical called sodium borohydride. Once the storage problem is solved and standardized, then a network of hydrogen stations and the transportation infrastructure will have to develop around it. The main barrier to this might be the technological sorting-out process. Stations will not develop quickly until there is a storage technology that clearly dominates the marketplace. For instance, if all hydrogen-powered cars from all manufacturers used sodium borohydride, then a station network could develop quickly; that sort of standardization is unlikely to happen rapidly, if history is any guide.
Prospects for the future
You will hear more and more about the hydrogen economy in the news in the coming months, because the drumbeat is growing louder. The environmental problems of the fossil fuel economy are combining with breakthroughs in fuel-cell technology, and the pairing will allow us to take the first steps.
The most obvious step we will see is the marketing of fuel-cell-powered vehicles. Although they will be powered initially by gasoline and reformers, fuel cells represent two major improvements over the internal combustion engine:
They are about twice as efficient.
They can significantly reduce air pollution in cities.
1. The passage gives a general description of the benefits and potential problems of a hydrogen economy.
2. An oil spill can pose a big problem to the environment.
3. Compared with other major industrialized countries, the United States depends more heavily on oil import.
4. Even if you have electricity and water, you still cannot produce hydrogen everywhere.
5. In the United States, most of the electricity is generated from coal or natural gas.
6. We must derive hydrogen from renewable sources with a view to a pure hydrogen economy.
7. So far, there seems to be no solution in sight as to how the hydrogen can be stored.
1. [Y] [N] [NG] 2. [Y] [N] [NG] 3. [Y] [N] [NG] 4. [Y] [N] [NG]
5. [Y] [N] [NG] 6. [Y] [N] [NG] 7. [Y] [N] [NG]
8. Possible sources for the hydrogen are both electrolysis of water and .
9. If the storage problem is and , a network of hydrogen stations and the transportation infrastructure will have to develop around it.
10. Concerning the future of the hydrogen economy, the most obvious step we will take is .
Part III Listening Comprehension (35 minutes)
Section A
Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked [A], [B], [C] and [D], and decide which is the best answer. Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre.
11. [A] He looks happier lately.
[B] He manages his time well.
[C] He’s improved the way he looks.
[D] He follows directions more carefully now.
12. [A] He agrees with the woman.
[B] He hasn’t been to a game recently.
[C] He doesn’t know much about baseball.
[D] He doesn’t think the team has been playing well.
13. [A] He suggests they go to the class.
[B] He suggests that they don’t go to the class.
[C] He suggests she should forget about the class.
[D] He suggests they attend the class, but slip from it halfway.
14. [A] He doesn’t put his ideas into practice.
[B] He doesn’t have many good ideas.
[C] He has too many dreams.
[D] He likes sleeping much.
15. [A] The man should see a doctor.
[B] She will help the man change his diet.
[C] She understands why the man seems unhappy.
[D] The doctor has already explained the problem to her.
16. [A] If he can help her fill out a job application.
[B] If he can introduce her to the camp counselor.
[C] If he knows of any job openings with his former employer.
[D] If hell be returning to the camp where he worked last year.
17. [A] He went to see the dentist a week ago.
[B] The woman should cancel her appointment with the dentist.
[C] The woman’s toothache will go away by itself.
[D] The woman should have seen the dentist earlier.
18. [A] Ask Johnston one more time.
[B] Ask Johnston to extend the deadline.
[C] Ask Johnston to clarify the submission date.
[D] Ask Johnston to spend more time explaining.
Questions 19 to 22 are based on the conversation you have just heard..
19. [A] He can’t find his office key.
[B] He has misplaced some exams.
[C] He is unable to talk.
[D] He doesn’t like his classroom.
20. [A] Mark the latest homework assignment.
[B] Put a cancellation notice on the classroom door.
[C] Make an appointment with the doctor.
[D] Return some exams to his students.
21. [A] Teach David’s class while he is absent.
[B] Give Professor Winston the key to David’s office.
[C] Leave a message on the board in David’s classroom.
[D] Bring David the homework that was due today.
22. [A] To put the homework on David’s desk.
[B] To leave the master key for David.
[C] To give David’s students the next assignment.
[D] To call David at the end of the afternoon.
责任编辑：虫虫
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