请输入或粘贴题目内容
搜题
拍照、语音搜题，请扫码下载APP
题目内容
（请给出正确答案）
A．Y
B．N
C．NG
答案
更多“The periods of light and darkness the moon created were the first accepted periods of time”相关的问题
第1题
A new study from Switzerland, sheds light on (使某事清楚明白地显示) where ice sheets (冰川) melted during the ice age. It now seems that the ice melted at both ends of the earth, rather than just in either northern or southern regions (区域).
This surprised the researchers from the University of Bern (伯恩大学). Scientists have long assumed (假设) that most of the ice that melted was in the Northern hemisphere (半球) during the 30,000 year long ice age. That belief was held because the North Pole is surrounded by land, while the South Pole is surrounded by the Antarctic Ocean. It is easier for ice sheets to grow on land. If surrounded by sea the ice can easily just slip into the ocean instead of building up.
The researchers used a computer model to look at ways the ice could melt and how it might affect sea levels. They compared these results to evidence (证据) of how temperatures and currents actually changed during that time. The model showed that if it was only in the Northern hemisphere that ice melted, there would have been a bigger impact (影响) on ocean currents (流) and sea temperatures than what actually happened. Studies suggest that melting just in the Southern hemisphere would have been impossible, too. The only reasonable conclusion, the scientists could make, was that ice melted equally in the North and the South.
It is still a mystery (神秘的事物) as to what caused the temperature changes that caused the ice to melt.
The North Pole is surrounded by land, while the South Pole is surrounded by the Antarctic Ocean. So scientists thought that______.
A．most of the ice melted in the Northern hemisphere
B．most of the ice melted in the Southern hemisphere
C．The North Pole is colder than the South Pole
D．The South Pole is colder than the North Pole
第2题
Mystery of Time
If you can read a clock, you can know the time of day. But no one knows what time itself is. We can not see it. We can not hear it. We know it only by the way we mark its passing. For ail our success in measuring the tiniest parts of time, time remains one of the great mysteries of the universe.
One way of thinking about time is to imagine a world without time. There could be no movement, because time and movement can not be separated. A world without time could exist only as long as there were no changes, for time and change are linked. When something changes, you know time has passed. In the real world, changes never stop. Some changes happen only once in a while, like an eclipse of the moon. Others happen repeatedly, like the rising and setting of the sun. People have always noted natural events that repeat themselves. When people began to count such events, they began to measure time.
In early human history, the only changes that seemed to repeat themselves evenly were the movements of objects in the sky. The most easily seen result of these movements was the difference between light and darkness.
The sun rose in the eastern sky, producing light. It moved overhead and sank in the western sky, causing darkness. The appearance and disappearance of the sun was even and unfailing. The periods of light and darkness it created were the first accepted periods of time. We have named each period of light and darkness one day. People saw the sun rise higher in the sky during the summer than in winter. They counted the days that passed from the sun's highest position until it returned to that position. They counted 365 days. We now know that is the time Earth takes to move once around the sun. We call this period of time a year.
Early humans also noted changes in the moon. As it moved across the night sky, they must have wondered. Why did it look different every night？ Why did it disappear？ Where did it go？
Even before they learned the answers to these questions, they developed a way to use the moon's changing faces to tell time. The moon was "full" when its face was bright and round. They counted the number of times the sun appeared between full moons. They learned that this number always remained the same, about 29 suns. Twenty-nine suns equaled one moon. We now know this period of time as one month.
Early people hunted animals and gathered wild plants. They moved in groups, or tribes, from place to place in search of food. Then people learned to plant seeds and grow crops. They learned to raise animals. They found they no longer needed to move from one place to another to survive. As hunters, people did not need a way to measure time. As farmers, however, they had to plant crops in time to harvest them before winter. They had to know when the seasons would change. So they developed calendars.
No one knows when the first calendar was developed. But it seems possible that it was based on moons, or lunar months. When people started farming, the wise men of the tribes became very important. They studied the sky. They gathered enough information to be able to say when the seasons would change. They announced when it was time to plant crops.
The divisions of time we use today were developed in ancient Babylonia 4,000 years ago. Babylonian astronomers believed the sun moved around the Earth every 365 days. They divided the trip into 12 equal parts or months. Each month was 30 days. Then they divided each day into 24 equal pans, or hours. They divided each hour into 60 minutes, and each minute into 60 seconds.
Humans have used many devices to measure time. The sundial was one of the earliest and simplest. A sundial measures the movement of the sun across the sky each day. It has a stick or other object that rises above a flat surface. The stick, blocking sunlight, creates a s
A．Y
B．N
C．NG
第3题
Seated Exercise Series: Chair Aerobics
When most people think of exercise, they usually think of things like running, jogging, jumping rope, lifting heavy weights, and so on. And all of these weight-bearing exercises involve the bones and muscles working against gravity. If you have problems standing for long periods of time, Chair Aerobics is the exercise for you.
Chair Aerobics lets you exercise your body while sitting in a chair. Consider the following:
Chair aerobics is performed for about 20-30 minutes and consists of rhythmic movements.
It is a low-impact exercise with almost no potential for damage to joints and enables you to perform. your daily routine activities effectively.
It lets you move your arms and legs to music while taking the weight off your feet.
You don't need special clothes, shoes, or space.
No equipment other than a chair is required.
Like any other physical exercise, it can improve your muscle tone, flexibility, and posture.
Chair Aerobics for Everyone is a great exercise video for men and women of all ages.
Included in the training video: Upper Body Workout Lower Body Workout Abdominal Toning Cool-down
Newington Health & Wellness Co.
Newington Town Hall 131 Cedar St,
Newington, CT 06111
Phone: (860) 665-8500 / M-F 8:30 a.m.-4:30 p.m.
Total Health Magazine
Fall 2007
Which machine is your favorite？
People do not always burn the same number of calories on one exercise machine as on another.
A recent study was conducted on the number of calories expended by healthy men and women in their twenties while they exercised on four different machines. The intensity of their exercise was categorized as "fairly light" , "somewhat hard" , or "hard" and showed the following results:
Both men and women burned the most calories on the treadmill and the least on the stationary bicycles.
The stair climber and the rowing machine were in the middle for both men and women.
Whatever the equipment is, that men burned more calories than women did is the physiological fact that pound for pound, men have more muscle than women, and muscles burn more calories than fat does. In addition, it takes more calories to move a larger person and men are usually bigger than women.
Be sure to consult a trainer before starting any of these exercise programs as they involve impact pressure, which is often associated with physical injury.
What is NOT mentioned in the advertisement as a conventional form. of exercise？
A．Basketball
B．Jogging
C．Running
D．Weight lifting
第4题
It is a very interesting question why some people remember dreams regularly—perhaps several a night on occasion—while others remember hardly any at all under normal conditions. In considering this, it is important to bear in mind that the dream tends to be an elusive phenomenon for all of us. We normally never recall a dream unless we awaken directly from it, and even then it has a tendency to fade quickly into oblivion.
Given this general elusiveness of dreams, the basic factor that seems to determine whether a person remembers them or not is the same as that which determines all other memory, namely degree of interest. Dream researchers have made a broad classification of people into "recallers" —those who remember at least one dream a month—and "non-recallers", who remember fewer than this. Tests have shown that cool, analytical people with a very rational approach to their feelings tend to recall fewer dreams than those whose attitude to life is open and flexible. Engineers generally recall fewer dreams than artists. It is not surprising to discover that in western society, women normally recall more dreams than men, since women are traditionally allowed an instinctive, feeling approach to life.
In modern urban-industrial culture, feeling and dreams tend to be treated as frivolities which must be firmly subordinated to the realities of life. We pay lip-service to the inner life of imagination as it expresses itself in the arts, but in practice relegate music, poetry, drama and painting to the level of spare-time activities, valued mainly for the extent to which they refresh us for a return to work. We discourage our children from paying much attention to anything that might detract from the serious business of studying for exams or making a living in the "real" world of industry and commerce.
Many people are unaware that they dream because ______.
A．their dreams fade very quickly
B．they do not recall their dreams
C．they sleep too heavily
D．they wake up frequently
第6题
A.63 bit periods
B.133 bit periods
C.2048 bit periods
第9题
The American dream is most plausible(似乎可信的)during the periods of productivity and wealth______by American capitalism.
A．generated
B．excited
C．inspired
D．prompted
