填空题
Cyclones are huge revolving storms caused by winds blowing around a central area of low at-mospheric pressure. In the northern hemisphere, cyclones, called hurricanes or typhoons, blow in an anti-clockwise direction. In the southern hemisphere, these tropical storms are known as cy-clones, whose winds blow in a clockwise direction.
Cyclones develop over warm seas near the Equator. Air heated by the sun rises very swiftly creating areas of very low pressure. As the warm air rises, its moisture condenses into massive thun-derclouds. Cool air rushes in to fill the void that is left, but because of the constant turning of the Earth on its axis, the air is bent inwards and then spirals upwards with great force. The swirling winds rotate faster and faster, forming a huge circle which can be up to 2, 000 km across. At the centre of the storm is a calm, cloudless area called the eye, with no rain, and fairly light winds. As the cyclone builds up it begins to move, and is sustained by a steady flow of warm, moist air. The strongest winds and heaviest rains are found in the towering clouds which merge into a wall about 20-30 km from the storm' s centre. Winds around the eye can reach speeds of up to 200 kin/h, and a fully developed cyclone pumps out about two million tons of air per second. This results in more rain being released.
Cyclones are dangerous for people living around tropical areas. The most destructive force of a cyclone is the fierce winds. These winds are strong enough to topple fences, sheds, trees, power poles and caravans easily. A cyclone typically churns up the sea, causing giant waves and surges of water known as storm surges which rush inland with deadly power, flooding low-lying coastal areas.
Fill in each blank in no more than three words according to the passage.

What Is a Cyclone?
Definition	Large circling storms with strong winds blowing around a central area.
Location	These storms form near the (56) over open water. They are called hurricanes and typhoons in the northern hemisphere, and cyclones in the southern hemisphere.
Causes	1. The warm moist air rises and turns into thunderclouds.
	2. Cool air flows in to fill the (57) left by the rising air.
	3. The earth' s movement makes the air bend inward and (58) upwards. The swirling winds rotate faster and faster.
	4. As the cyclone builds it begins to move.
Elements	A. Towering clouds become a wall around the storm's centre.
	C. Heaviest rainfall is in the "wall".
Effects	Winds can knock over trees, houses, fences, power poles, etc.
	Churns up the sea into giant waves and (60) which cause flooding.