更多"How do the professional timekeepers"的相关试题:
[单项选择]How do the professional timekeepers of the world determine, to the precise nanosecond, when a new year begins They simply consult an atomic clock. At the end of last month, just in time to ring in the new year, the Hewlett-Packard company, of Palo Alto, California, unveiled the latest of these meticulous time- pieces. For nearly 30 years, the firm has been supplying military and scientific clients with atomic clocks; the most advanced models neither gain nor lose more than a second every 800,000 years. But the newest version, a $54,000 device the size of desktop computer, is accurate to one second in 1.6 million years — far longer than all of human history to date.
It is natural to wonder who could possibly need such precision. The answer: practically everyone, at least indirectly. Telephone and computer networks rely on atomic clocks to synchronize the flow of trillions of bits of information around the nation and the world, thus avoiding mammoth electronic logjams. Television
A. a second in 30 years.
B. a second every 800,000 years.
C. a second every million years.
D. a second in 1,6 million years.
[简答题]part 2Event
Describe a family event
How do you define happiness
Describe a recent event that has made you happy
Do you think money is important
Do you think money can give you happiness
Can old people get happiness？
[单项选择]How do schools deal with students who experience difficulties
A. They are given appropriate supplementary tuition.
B. They are encouraged to copy from other pupils.
C. They are forced to explain their slow progress.
D. They are placed in a mixed-ability class.
[单项选择]
How do they feel
A. Tired.
B. Surprised.
C. Angry.
[单项选择]How did Mexico do in the 1970 World Cup（）
A. It wasn’t among the top four teams.
B. It didn’t play as well as expected.
C. It won the World Cup.
D. It placed fourth.
[单项选择]
How do the fans respond to Elvis’drug dependency and other excessive behavior
A. They regret for them.
B. They just ignore them.
C. They sharply criticize them.
D. They follow his behavior.
[单项选择]How exactly, does science work How do scientists go about doing science Ordinarily we think science proceeds in a straight-forward way. Ideally scientists make observations, formulate hypotheses (假设), and test those hypotheses by making further observations. When there is difference between what is observed and what is predicted by the hypothesis, the hypothesis is revised. Science proceeds in this way, which is a gradual method of finding the best fit between observation and prediction.
But this idealized version of how one does science is naive. Although science demands proof that observations made by one observer be observable by other observers using the same methods, it is by no means dear that, even when confronted with identical phenomena, different observers will report identical observations. And it is most certain that, even if the same observations are made, the conclusions as to the meaning of the observations frequently differ.
The fact is that all of us, s
A. are related to the methods of observation
B. can never be avoided
C. are caused by human perceptual mechanism
D. can easily be corrected
[多项选择] What do you do to unwind How do you relax your mind
