Hurricane Katrina
A hurricane is n fiercely powerful , rotating form of tropical storm that can be 124 to 1,240 miles in diameter. The term hurricane is derived from Hurican, the name of 8 native American storm god1. Hurricanes are typical of2 a calm central region of low pressure between 12 to 60 miles in diameter, known as the eye. They occur in tropical regions. Over its lifetime3, one of these storms can release as much energy as 10,000 nuclear bombs4.
The seed for hurricane formation5 is a cluster of thunderstorms over warm tropical waters. Hurricanes can only form and be fed6 when the sea-surface temperature exceeds 270C and the surrounding atmosphere is calm. These requirements are met between June and November in the northern hemisphere.
Under these conditions, large quantities of water evaporate and condense into clouds and rain — releasing heat in the process. It is this heat energy, combined with the rotation of the Earth, that drives a hurricane.
When the warm column of air7 from the sea surface first begins to rise, it causes an area of low pressure. This in turn creates wind as air is drawn into the area. This spinning wind drags up more moisture-laden air from the sea surface in a process that swells the storm8. Cold air falls back to the ocean surface through the eye9 and on the outside of the storm.
Initially, when wind speeds reach 23 miles per hour, these mild, wet and grey weather systems are known as depressions10. Hurricane Katrina formed in this way over the southeastern Bahamas on 23 August 2005. Katrina has had a devastating impact on the Gulf Coast of the US, leaving a disaster zone of 90,000 square miles in its wake11 — almost the size of the UK. Thousands have been killed or injured and more than half a million people have been displaced in a humanitarian crisis of a scale not seen in the US since the great depression.12 The cost of the damage may top13 $ 100 billion.词汇: hurricane / 5hQrikEn /n.飓风 evaporate /i5vApEreit/v.(使)蒸发，(使)挥发 rotate / rEu5teit /v.旋转，转动 condense /kEn5dens/v.使冷却凝结;使浓缩 cluster /5klQstE/n.一群,一束 moisture-laden adj.充满水分的，充满湿度的 thunderstorm n.雷暴 sustain /sEs5tein/v.保持，持续 hemisphere /5hemisfiE/n.(地球的)半球 humanitarian / hju(:)7mAni5tZEriEn/adj.人道主义的注释:
1. storm god:风暴之神。原为加勒比海 (Caribbean-Sea)地区加勒比人心目中的“罪恶之神” (the god of evil)。
2. are typical of:以……为特征，有……特点。
3. over its lifetime:在(飓风)肆虐的整个过程中
4. release as much energy as 10,000 nuclear bombs:释放相当于 l万颗核弹的能量
5. The seed for hurricane formation: 飓风形成的原因。 seed原义为“种子”，在这里的意思是“原因”。
6. ... be fed: feed在这里的意思是 : to supply with something essential for growth, maintenance, or operation (为生长、维持或运行提供某些必要的物质条件 )，在此可理解为“引发”。
7. the warm column of air:柱状暖气流
8. a process that swells the storm:增大暴风雨威力的变化过程。 swell:在此作动词用，意思是 to cause to increase in volume, size, number, degree, or intensity (增强体积、尺寸、数量、程度或强度 )。
9. the eye:指第一段中提到的“飓风中心”。
10. depressions:低气压区
11. in its wakes在……之后。例如 : The car left clouds of dust in its wake.车后扬起了一阵尘土。
12. … more than half a million people have been displaced in a humanitarian crisis of a scale not seen in the US since the great depression:五十多万人被迫离开家园，如此大规模的人道主义危机是美国自大萧条以来还未经历过的。 be displaced:被迫离开某地。 the great depression:大萧条，指从 1929年开始、持续至大约 1939年在北美洲、欧洲和世界其他工业化地区发生的经济衰退。
13. top:在此作动词用，意思是 to exceed or surpass(多于，越过 )。练习:
1. What is the eye of a hurricane? A A native American storm god.
B A rotating form of tropical storm that can be 124 to 1240 miles in diameter. C A calm central region of low pressure between 12 to 60 miles in diameter. D A storm that can release as much energy as 10,000 nuclear bombs.
2. Which of the following is NOT the “requirements” mentioned in the second paragraph? A The tropical waters are warm and calm. B The sea-surface temperature exceeds 27°C. C There are thunderstorms over warm tropical waters. D The atmosphere surrounding the sea is calm.
3. Which of the following is the best explanation of the word “drive” in the third paragraph? A To guide, control, or direct. B To force to go through or push in. C To supply the motive force or power and cause to function. D To force to move in a particular direction.
4. What does the warm air mentioned in the fourth paragraph produce when it is rising from the sea surface? A High pressure. B Low pressure. C Wind. D Cold air.
5. What is NOT true of Hurricane Katrina according to the last paragraph? A The area affected is almost the size of the UK. B It left a disaster zone of 90,000 square miles. C Half a million people are forced to leave the area. D The humanitarian crisis is as serious as that of the great depression.
答案与题解 :
1. C 文章的第一段第三句描述了飓风的特点，即一个直径为 12～60英里的、平静的低气压中心地带。这个中心就叫做 eye of a hurricane。
2. A第二段的第一、二句描写飓风的形成原因，昀后一句中的 These requirements即是第一、二句中所述内容。所以 B、C和 D都不是正确选项。
3. C A的意思是“驾驶”;B的意思是“敲”，“打”、“击”，如: Drive in a nail.把钉子敲进去。 D的意思是“驱赶”，如: Drive the cattle along the road.沿大路驱赶牛群。 C的意思是“发动”、“驱动”，是正确选项。
4. B第四段第一句提供了答案。… it causes tan area of low pressure. it代指从海面上升起来的暖流。
5. D A、B、C的内容均在课文昀后一段中被提到。文中… in a humanitarian crisis of a scale not seen in the US since the great depression.的大致意思是 :如此大规模的人道主义危机是美国自大萧条以来还未约历过的。 D句不符合这句话的意思，所以是正确选项。
