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Passage One
Questions 21 to 25 are based on the following passage.

One pertinent question in the wake of the earthquake near Aceh (ÑÇÆëÊ¡) and the tsunami (º£Ð¥) it generated is how much notice of an approaching wave can be given to vulnerable people without the risk of crying ¡°wolf¡± too often. Earthquakes themselves are unpredictable, and likely to remain so. But detecting them when they happen is a routine technology. That was not the problem in this case, which was observed by monitoring stations all over the world. Unfortunately for the forecasters, although any powerful submarine earthquake brings the risk of a dangerous tsunami, not all such earthquakes actually result in a big wave, and false alarms cost money and breed cynicism.

On top of that, most ¡°tsunamigenic¡± earthquakes, which are caused when the processes of plate tectonics force heavy, oceanic crustal rock below lighter, continental rock to create a deep trench at the bottom of the sea, occur in the Pacific, which is almost surrounded by such trenches. In the Indian Ocean, deep trenches are confined to the southern coast of Indonesia, and tsunamis are rare. Since most of the countries affected by this tsunami are poor, or middleª²income at best, and monitoring costs money, this might suggest that a fatalistic approach to the question is reasonable. But American and Japanese experience suggests that effective monitoring need not be that expensive.
These two countries have networks of seabed pressureª²detectors that can monitor tsunamis and indicate whether and where evacuation is necessaryª²data they share with their Pacific neighbours. A system of seven detectors, run from Hawaii, cost about $18m to develop, and the experience gained doing so means a similar system might now be had for as little as $2m. So, to the sound of stable doors being bolted firmly shut, politicians in Southª²East Asia and Australia are proposing one for the Indian Ocean.

Even if you have an effective detection system, though, it is useless if you cannot evacuate a threatened area. Here, speed is of the essence. Computer modelling can help show which areas are likely to be safest, but common sense is often the best guideª²run like the wind, away from the sea. Evacuation warnings, too, should be easy to give as long as people are awake. Radios are ubiquitous, even in most poor places. It is just a matter of having systems in place to tell the radio stations to tell people to run. The problem was that no one did.

21. An important question raised after the Tsunami is that ______ .
A) how to help those helpless people
B) how to detect the happening of tsunami
C) how to predict tsunamigenic earthquakes
D) how people should be cautiously warned

22. To the forecasters, the troublesome problem is ______ .
A) it¡¯s hard to tell disastrous submarine earthquake
B) people don¡¯t take much notice of their warning
C) tsunamis are rare
D) where to get money for the false alarms

23. Which of the following is true according to the passage?
A) Big waves depend on the intensity of earthquake.
B) Most earthquakes that cause tsunamis happen in the Pacific.
C) Tsunamis often occur along the coast of Indonesia.
D) Trenches at the bottom of the sea create tsunamis.

24. To the countries in Southª²East Asia, building a tsunami monitoring system ______ .
A) is what they can not afford
B) is not a practical solution
C) won¡¯t cost a lot of money
D) is effective but expensive

25. It is implied in the last paragraph that ______ .
A) people should be taught how to escape the tsunami
B) a sound detection system could have saved the disaster
C) radio stations neglected their responsibilities
D) the heavy loss in the Southª²East tsunami could have been less

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