AN INCREASED NUMBER OF CITY DWELLERS HAS MADE THE OBSOLETE INFRASTRUC...
Câu 5: An increased number of city dwellers has made the obsolete infrastructure worse and
required a lot of repairs in these days.
A. has made
B. obsolete infrastructure
C. required
D. repairs
Read the passage and choose the correct answer to each of the questions
from 6 to 10.
Ocean water plays an indispensable role in supporting life. The great ocean basins hold about
300 million cubic miles of water. From
this vast amount, about 80,000 cubic miles of water
are sucked into the atmosphere each year by evaporation and returned by precipitation and
drainage to the ocean. More than 24,000 cubic miles of rain descend annually upon the
continents. This vast amount is required to replenish the lakes and streams, springs and water
tables on which all flora and fauna are dependent. Thus, the hydrosphere permits organic
existence. The hydrosphere has strange characteristics because water has properties unlike those
of any other liquid. One anomaly is that water upon freezing expands by about 9 percent,
whereas most liquids contract on cooling. For this reason, ice floats on water bodies instead of
sinking to the bottom. If the ice sank, the hydrosphere would soon be frozen solidly, except for
a thin layer of surface melt water during the summer season. Thus, all aquatic life would be
destroyed and the interchange of warm and cold currents, which moderates climate, would be
notably absent. Another
outstanding
characteristic of water is that water has a heat capacity
which is the highest of all liquids and solids except ammonia. This characteristic enables the
oceans to absorb and store vast quantities of heat, thereby often preventing climatic extremes. In
addition, water dissolves more substances than any other liquid. It is this characteristic which
helps make oceans a great storehouse for minerals which have been washed down from the
continents. In several areas of the world these minerals are being commercially exploited. Solar
evaporation of salt is widely practiced, potash (KCO3) is extracted from the Dead Sea, and
magnesium is produced from sea water along the American Gulf Coast.