大学英语第四单元习题

In the second half of each year, many powerful storms are born in the warmer southern Atlantic and Caribbean seas. Of these, only about a half a dozen create the strong, circling winds of 75 miles per hour or more that can cause great harm, 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 winds 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, wet air flows in at the bottom of these winds, moves upward through it, and comes out at the top. In the process, the water in this warm air produces rain. And the heat is changed to energy in the form of strong winds. As the heat increases, the young storm begins to move in circles, turning in the direction opposite to the movement of a clock's hands.

The average life of a strong storm of this type is only about nine days, but it contains almost more power than we can imagine. The energy in the heat given by a great storm's rainfall in a single day would satisfy the entire electrical needs of the United States for more than six months. Water, not wind, is the main source of death and damage in a great storm. One of these storms usually brings 6 to 12 inch downpours resulting in sudden floods. Worst of all is the powerful movement of the sea—the mountains of water moving toward the low-pressure storm center. The water level rises as much as 15 feet above normal as it moves toward shore.

1. This passage describes __________.

A. the growth of great storms

B. the damage caused by great storms

C. the average life of a great storm

D. All of the above

2. The powerful storms described in this passage have winds that move at __________.

A. 75 miles per hour or more

B. less than 75 miles per hour

C. half a dozen miles per hour

D. 75 miles per hour

3. According to the passage, the growth of a great storm goes through the following steps:

A. small winds—trade winds—air flows—wet air—rain—heat—strong wind

B. wet air—trade winds—strong wind—rain—warm winds—heat—air flows

C. small winds—wet air—trade wind—strong wind—air flows—heat—rain

D. wet air—trade wind—strong wind—heat—air flows—small winds—rain

4. According to the passage, the energy in the heat given by a great storm's rainfall in a single day would _______________________________.

A. destroy half of the farmlands in the United States within one hour