【单选题】

In the second half of each year, many powerful storms are (31) in the tropicalAtlantic andCaribbean seas. Of these, only about a half dozen (32) the strong, circling winds of 75 miles per hour or more that give them hurricane (33) , and several usually (34) to the coast. There they cause (35) damage, and bring death to large number of people.

The great storms that hit the coast start (36) innocent circling disturbances hundreds—even thousands—of miles out to seA、As they travel aimlessly over water (37) by the summer sun, they are carried westward by the trade winds. When (38) are just right, warm, moist air flows in at the bottom of such a disturbance, (39) upward through it and comes out at the top. In the process, the (40) in this warm air produces rain, and with it the heat is (41) to energy (42) strong winds. (43) the heat increases, the young hurricane begins to swirl in a counter-clockwise motion.
The average life of a hurricane is only about nine days, (44) it contains almost more power than we can imagine. The energy in the heat (45) by a hurricane’s rainfall in a(n) (46) day would satisfy the entire (47) needs of the United States for more than six months. Water, not wind, is the main (48) of death and destruction in a hurricane.A、typical hurricane brings 6-12-inch downpours resulting (49) sudden floods. Worst of all is the powerful movement of the sea-the mountains of water moving toward the low-pressure hurricane center. The water level rises as (50) as 15 feet above normal as it moves toward shore.
A．moving
B．moved
C．moves
D．which moves