Several regions in the world are

Several regions in the world are subject 21_______ storms which are so severe that they cause damage on a tremendous scale. The regions are all located on the edges of great oceans. The 22_______ term for such severe storms is “cyclone”(龙卷风). The term “hurricane” is 23_______ for storms that occur in the North Atlantic Ocean.
Cyclones and hurricanes differ in one curious 24_______ : in a cyclone, the wind circulates in a clockwise direction; in a hurricane, the wind direction is counter-clockwise. 25_______ cyclones and hurricanes have one ominous similarity. 26_______ the damage they cause on land and at sea， they are identical.
Australia undergoes a number of cyclones every year along its northern coast, which faces Indonesia. The cyclones occur mainly in December and January, the summer months in the southern hemisphere.
27_______ the Australian cyclones don’t cause great damage because Australia’s northern territory has vast empty regions that are virtually unpopulated. There are 28_______ coastal cities. When a cyclone does move inland from the sea, it usually blows itself out without 29_______ any inhabitated area. However, in 1917 the small city of Townville was 30_______ devastated by a cyclone. There was a public outcry about it. People demand an adequate warning system. Ever since then the meteorological bureau has regularly issued alarms in advance of every serious cyclone.
25.
A、However
B、And
C、But
D、Then
【正确答案】：C