Today ,as in every other day of the year ,more than 3000 U.S. adlescents will smoke their first cigarette on their way to becoming regular smokers as adults. During their lifetime,it can be expected that of these 3000 about 23 will be murdered,30 will die in traffic accidents, and nearly 750 will be killed by a smoking-related disease. The number of deaths attributed to cigarette smoking outweithts all other factors, whether voluntary or involuntary, as a cause of death. Since the late 1970s, when daily smoking among high school seniors reached 30 precent , smoking rates among youth have declined . While the decline is impressive ,several important issues must be raised. First, in the past several years,smoking rates among youth have declined very little. Second,in the late 1970s ,smoking among male high school seniors exceeded that among female by nearly 10 percent . The statistic is reversing.Third ,several recent studies have indicate high school dropouts have excessively high smoking rates, as much as 75 percent . Finally, thouth significant declines in adolescent smoking have occurred in the past decade,no definite reasons for the decline exist. Within this context,the Naional Cancer Instiute (NCI) began its current effort to determine the most effecive measures to reduce smoking levesl among youth. What is implied but not stated by the author is that ().
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B
The word “day” has two meanings. When we talk about the number of days in a year, we are using “day” to mean 24 hours. But when we talk about day and night, we are using “day” to mean the time between sunrise and sunset. Since the earth looks like a ball, the sun can shine on only half of it at a time. Always one half of the earth is having day and the other half night. A place is moved from day into night and from night into day over and over by the spinning(旋转) of the earth. At the equator(赤道) day and night are sometimes the same length. They are each twelve hours long. The sun rises at 6 in the morning and sets at 6 in the evening. For six months the North Pole is tilted(倾斜) toward the sun. In those months the Northern Hemisphere(半球) gets more hours of sunlight than the Southern Hemisphere. Days are longer than nights. South of the equator nights are longer than days. For the other six months the North Pole is tilted away from the sun. Then the Southern Hemisphere gets more sunlight. Days are longer than night. North of the equator nights are longer than days. Winter is the season of long nights. Summer is the season of long days.
56. When the Western Hemisphere is having day, the Eastern Hemisphere is having ______.
A.both day and night B.day C.neither day nor night D.night
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but
however
if
otherwise
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the U.S. enjoyed more than any time in its history peace and economic well being
the U.S. enjoying more than any other time in its history peace and economic well being
more peace and economic well being was enjoyed by the U.S. than any other time
economic peace and well being was enjoyed by the U.S. more so than any other ~ time in the country’s history
the U.S. enjoyed more peace and economic well being than at any other time in its history
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HIV was found more than two years earlier than AIDS was identified
people know a little more about HIV than about most other viruses
AIDS continues to rage more wildly in Africa than in Asia
HIV will mainly affect the poor and minority groups in the U.S.
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Thousands of
Two thousands
Thousand of
Thousand
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Not all of Zorba’s competitors use kalamata olives in their oil.
Zorba’s sells more olive oil than any other company.
The most flavorful olive oil is not necessarily the best olive oil.
Because of bulk discounts, Zorba’s pays less per kilogram of kalamata olives than does its competitors.
The number of kalamata olives harvested every year is far less than the number of Spanish olives harvested every year.
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They indicate that sediments found during an ice age contain more calcium carbonate than sediments formed at other times.
They are less reliable than the evidence from rocks on land in determining the volume of land ice.
They can be used to deduce the relative volume of land ice that was present when the sediment was laid down.
They are more unpredictable during an ice age than in other climatic conditions.
They can be used to determine atmospheric conditions at various times in the past.