模拟彩色电视制式中,()制式的场扫描频率为50场/秒。NTSC制式的电视信号帧速率为(),通常胶片电影的快门速率为()。 模拟彩色电视制式中,()制式的场扫描频率为50场/秒。
A. NTSC
B. PAL 和 SECAM
C. SECAM 和 NTSC
D. PAL 和 NTSC
E The most frightening words in the English language are, “Our computer is down.” You hear it more and more when you are on business. The other day I was at the airport waiting for a ticket to Washington and the girl in the ticket office said, “I’m sorry, I can’t sell you a ticket. Our computer is down.” “If your computer is down, just write me out a ticket.” “I can’t write you out a ticket. The computer is the only one allowed to do so.” I looked down on the computer and every passenger was just standing there drinking coffee and staring at the black screen. Then I asked her, “What do all you people do” “We give the computer the information about your trip, and then it tells us whether you can fly with us or not.” “So when it goes down, you go down with it.” “That’s good, sir.” “How long will the computer be down” I wanted to know. “I have no idea. Sometimes it’s down for 10 minutes, sometimes for two hours. There’s no way we can find out without asking the computer, and since it’s down it won’t answer us.” After the girl told me they had no backup computer, I said. “Let’s forget the computer. What about your planes They’re still flying, aren’t they” “I couldn’t tell without asking the computer.” “Maybe I could just go to the gate and ask the pilot if he’s flying to Washington, ” I suggested. “I wouldn’t know what gate to send you to. Even if the pilot was going to Washington, he couldn’t take you if you didn’t have a ticket.” “Is there any other airline flying to Washington within the next few hours” “I wouldn’t know, ” she said, pointing at the dark screen. “Only ‘IT’ knows. ‘IT’ can’t tell me.” By this time there were quite a few people standing in lines. The words soon spread to other travelers that the computer was down. Some people went white, some people started to cry and still others kicked their luggage. The best title for the article is .
A. When the Computer Is Down
B. The Most Frightening Words
C. The Computer of the Airport
D. Asking the Computer
______ is present in the body in greater amounts than any other mineral.
A. Calcium
B. There is calcium
Calcium, which
D. It is calcium
Many theories concerning the causes of juvenile delinquency crimes committed by young people focus either on the individual or on society as the major contributing influence. Theories 16 on the individual suggest that children engage in criminal behavior 17 they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through 18 with others. Theories focusing on the role of society suggest that children commit crimes in 19 to their failure to rise above their socioeconomic status 20 as a rejection of middleclass values. Most theories of juvenile delinquency have focused on children from disadvantaged families, 21 the fact that children from wealthy homes also commit crimes. The latter may commit crimes 22 lack of adequate parental control. All theories, however, are tentative and are 23 to criticism. Changes in the social structure may indirectly 24 juvenile crime rates. For example, changes in the economy that 25 to fewer job opportunities for youth and rising unemployment 26 make gainful employment increasingly difficult to obtain. The resulting discontent may in 27 lead more youths into criminal behavior. Families have also 28 changes these years. More families consist of oneparent households or two working parents; 29, children are likely to have less supervision at home, 30 was common in the traditional family 31. This lack of parental supervision is thought to be an influence on juvenile crime rates. Other 32 causes of offensive acts include frustration or failure in school, the increased 33 of drugs and alcohol, and the growing 34 of child abuse and child neglect. All these conditions tend to increase the probability of a child committing a criminal act, 35 a direct causal relationship has not yet been established.
A. contrarily
B. consequently
C. similarly
D. simultaneously