A
In the second half of each year, many powerful storms are born in the tropical Atlantic and Caribbean seas.Of these, only about half a dozen generate the strong, circling winds of 75 miles per hour or more that give them hurricane status, and several usually make their way to the coast.There they cause millions of dollars of damage, and bring death to large numbers of people.
The great storms that hit the coast start as innocent circling disturbances (气旋) hundreds—even thousands—of miles out to sea.As they travel aimlessly over water warmed by the summer sun, they are carried westward by the trade winds.When conditions are just right, warm, moist (潮湿的) air flows in at the bottom of such a disturbance, moves upward through it and comes out at the top.In the process, the moisture in this warm air produces rain，and with it the heat is switched to energy in the form of strong winds.As the heat increases, the young hurricane begins to turn around in a counterclockwise motion (逆时针方向)．
The average life of a hurricane is only about nine days, but it contains almost more power than we can imagine.The energy in the heat released (释放) by a hurricane's rainfall in a single day would satisfy the entire electrical needs of the United States for more than six months.
Water, rather than wind, is the main source of death and destroying in a hurricane.A typical hurricane brings 6to12inch downpours resulting in sudden floods.Worst of all is the powerful movement of the sea—the mountains of water moving towards the lowpressure hurricane center.The water level rises as much as 15 feet above normal as it moves towards shore.
文章大意：文章讲述了飓风的形成过程——是达到每小时75英里以上的热带风暴形成的，和飓风给大自然和人类带来的巨大危害。
1．An ordinary tropical storm is called a hurricane when __B__.
A．it occurs in the Caribbean seas
B．its winds reach 75 miles per hour
C．it makes its way to the coastline
D．its winds begin to circle on the sea
解析：细节理解题。根据第一段第二句可知其中只有约一半会形成至少每小时75英里的强热带气旋，这样就会形成飓风，有些还会登陆海岸。
2．The counterclockwise movement of the hurricane is caused by __C__.
A．the lowpressure area in the center of the storm
B．the force of waves of water
C．the increasing heat
D．the trade winds
解析：细节理解题。根据第二段“As the heat increases，the young hurricane begins to turn around in a counterclockwise motion (逆时针方向)．”可知，当热度上升，刚产生的飓风就开始以逆时针方向盘旋。
3．What does the third paragraph mainly talk about？__A__
A．The hurricane is extraordinarily powerful.
B．The hurricane is used to generate electricity.
C．The hurricane can otherwise offer an unusual sight.
D．The hurricane can give people an unforgettable experience.
解析：段落大意题。第三段内容：一般一场飓风的持续时间大约是9天，但是它所携带的能量是我们无法想象的。飓风的降雨所释放的能量在一天里就可以满足整个美国6个多月的电力需要。
4．What is the worst thing about a hurricane？__A__
A．The rough water. B．The violent winds.
C．The heat it gives out. D．The length of its life.
解析：细节理解题。根据第四段“Water，rather than wind，is the main source of death and destroying in a hurricane.”可知，水是飓风造成死亡和破坏的主要因素，而不是风。
