[Trích dẫn tài liệu]
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.
Read the passage and choose the correct word or phrase that best fits each blank from 36 to 40.
If your reservations are booked far enough ___(36)___ of time, the airline may offer to mail your tickets to you. However, if you don’t receive the tickets and the airline’s records show that they mailed them, you may have to go through cumbersome lost-ticket procedures. It is safer to check the telephone ___(37)___ for a conveniently located travel agency or airline ticket office and buy your tickets there. As soon as you receive your ticket, check to make sure all the information on it is correct, especially the airports (if any of the cities have more than one) and the flight dates. Have any necessary corrections ___(38)___ immediately. It’s a good idea to reconfirm your reservations before you start your trip; flight schedules sometimes change. On international trips, most airlines require that you reconfirm your onward or return at ___(39)___ 72 hours before each flight. If you don’t, your reservations may be canceled. Check your ticket as you board each flight to ensure that only the correct coupon has been removed ___(40)___ the airline agent.
Read the passage and choose the correct answer to each of the questions from 44 to 50.
There is a common expression in the English language referring to a blue moon. When people say that something happens “only once in a blue moon,” they mean that it happens only very rarely, once in a great while. This has been around for at least a century and a half; there are references to this expression that date from the second half of the nineteenth century.
The expression “a blue moon” has come to refer to the second full moon occurring in any given calendar month. A second full moon is not called a blue moon because it is particularly blue or is any different in hue from the first full moon of the month. Instead, it is called a blue moon because it is so rare. The moon needs a little more than 29 days to complete the cycle from full moon to full moon. Because every month except February has more than 29 days, every month will have at least one full moon (except February, which will have a full moon unless there is a full moon at the very end of January and another full moon at the very beginning of March). It is on the occasion when a given calendar month has a second full moon that a blue moon occurs. This does not happen very often, only three or four times in a decade.
The blue moons of today are called blue moons because of their rarity and not because of their color; however, the expression “blue moon” may have come into existence in reference to unusual circumstances in which the moon actually appeared blue. Certain natural phenomena of gigantic proportions can actually change the appearance of the moon from Earth. The eruption of the Krakatoa volcano in 1883 left dust particles in the atmosphere, which clouded the sun and gave the moon a bluish tint. This particular occurrence of the blue moon may have given rise to the expression that we use today. Another example occurred more than a century later. When Mount Pinatubo erupted in the Philippines in 1991, the moon again took on a blue tint.