计算:19.98×37+199.8×2.3+9.99×80 答案:解:19.98×37+199.8×2.3+9.99×80 =19.98×37+19.98×23+(10-0.01)×80 =19.98×(37+23)+(10-0.01)×80 =19.98×60+10×80-0.01×80 =(20-0.02)×60+800-0.8 =20×60-0.02×60+800-0.8 =1200+800-(1.2+0.8) =2000-2 =1998A new study suggests that the more teenagers
watch television, the more likely they are to develop depression as young
adults .
The researchers used a
national long-term survey of adolescent(青少年的)health to investigate (调查)the relationship
between media use and depression. They based their findings on more than four
thousand adolescents who were not depressed when the survey began in 2000.
As part of the survey, the
young people were asked how many hours of television or videos they watched
daily. They were also asked how often they played computer games and listened
to the radio. Media use totaled an average of five and one-half hours a day.
More than two hours of that was spent watching TV.
Seven years later, in
2007, more than seven percent of the young people had signs of depression. The
average age at that time was twenty-one.
The researchers say they
did not find any such relationship with the use of other media such as movies,
video games or radio, etc. But the study did find that every extra hour of
television meant an eight percent increase in the chances of developing signs
of depression. Young men were more likely than young women to develop
depression given the same amount of media use.
The study didn't explore
if watching TV causes depression. But one possibility is that it was taking
time away from activities that could help prevent depression.
Last December, the journal
Social Indicators Research published a study of activities that help lead to
happy lives. Sociologists from the University of Maryland found that people who
describe themselves as happy spend less time watching television than unhappy
people. The study found that happy people are more likely to be socially
active, to read, to attend religious services and to vote.
1.The best title for this passage should be____________.
A. Teens, Television and Depression
B. Men Develop Depression Easier than
Women
C. Media Use is Harmful to
Adolescents
D. Take Great Care of Teenager's
Depression
2.The result of the research seems to prove______________.
A. teenagers are more likely to
develop depression than adults
B. other media uses do no harm to
adolescents
C. TV probably causes teenagers to
grow up with depression
D. those who watch no TV will not
develop depression
3.We can learn from the survey that of all the media use
A. computer games are teenagers'
favourite
B. most teenagers prefer to listen to
the radio
C. teenagers enjoy watching TV very
much
D. newspaper is not included in the
survey
4.We can conclude that a teenager should _____
A.
play more video games instead of watching TV
B. be
active in taking part in outdoor activities
C. be
more active in watching educational TV programmes
D.
attend religious services and care for politics