题目内容
（请给出正确答案）
42 Sunspots are cooler than the rest of the sun' s surface because
A they produce less energy．
B they are buried in the sun．
C they are far away from magnetic fields．
D they are close to magnetic fields．
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更多“42 Sunspots are cooler than th…”相关的问题
Why does the author mention "blemish," in paragraph 4？
A．To suggest that sunspots are flaws on the surface of the sun.
B．To illustrate that the sun is thought to have a face.
C．To emphasize that sunspots are indicative of illness.
D．To explain that microscopes are strong enough to see sunspots.
Sunspots are cooler than the rest of the sun's surface because
A．they produce less energy.
B．they are buried in the sun.
C．they are far away from magnetic fields.
D．they are close to magnetic fields.
请根据短文内容，回答题。
Sunspots （太阳黑子）
It&39;s not surprising that sunspots were observed by ancient astronomers (天文学家) . The largest sunspots on the sun can be seen without a telescope. It was not until the invention of the telescope (望远镜) in the early 17th century, however, that systematic studies of sunspots could be undertaken. The great astronomer Galileo was among the first to make telescopic observations of sunspots.＜br＞
Sunspots are regions of extremely strong magnetic fields (磁场) found on the sun&39;s surface. A sunspot has a dark central core known as the umbra. The umbra is surrounded by a dark ring called the penumbra, where the magnetic field spreads outward. Sunspots appear dark because they are giving off less radiation. They are cooler than the rest of the sun&39;s surface.＜br＞
Sunspots are frequently observed in pairs or in paired groups. The members of a spot pair are identified as the leading spot and the following spot. They are identified by their position in the pair in terms of the direction in which the sun rotates (旋转) .＜br＞
The number of sunspots at any one time varies. A large spot group may consist of as many as 10 groups and 300 spots across the sun. The number of spots changes in a fairly regular pattern called the sunspot cycle. The largest number occurs about every 11 years. At sunspot minimum, there are at most just a few small spots.＜br＞
The average lifetime of an individual spot group is roughly one solar rotation, which is about25 days. The most persistent large spots, however, can survive for two to three months.
Careful observations and systematic studies of sunspots __________. 查看材料
A.were made by ancient astronomers
B.started in the early 17th century
C.were made by Galileo only
D.could be made without a telescope
Sunspots
It's not surprising that sunspots (太阳黑子) were observed by ancient astronomers (天文学家). The largest sunspots on the sun can be seen without a telescope. It was not until the invention of the telescope (望远镜) in the early 17th century, however, that systematic studies of sunspots could be undertaken. The great astronomer Galileo was among the first to make telescopic observations of sunspots.
Sunspots are regions of extremely strong magnetic fields (磁场) found on the sun's surface. A sunspot has a dark central core known as the umbra. The umbra is surrounded by a dark ring called the penumbra, where the magnetic field, spreads outward. Sunspots appear dark because they are giving off less radiation. They are cooler than the rest of the sun's surface.
Sunspots are frequently observed in pairs or in paired groups. The members of a spot pair are identified as the leading spot and the following spot. They are identified by their position in the pair in terms of the direction in which the sun rotates (旋转).
The number of sunspots at any one time varies. A large spot group may consist of as many as 10 groups and 300 spots across the sun. The number of spots changes in a fairly regular pattern called the sunspot cycle. The largest number occurs about every 11 years. At sunspot minimum, there are at most just a few small spots.
The average lifetime of an individual spot group is roughly one solar rotation, which is about 25 days. The most persistent large spots, however, can survive for two to three months.
Careful observations and systematic studies of sunspots
A．were made by ancient astronomers.
B．started in the early 17th century.
C．were made by Galileo only.
D．could be made without a telescope.
A．undetermined
B．insignificant
C．unusual
D．indisputable
第三篇
Sunspots
It's not surprising that sunspots（太阳黑子）were observed by ancient astronomers（天文学家）．The largest sunspots on the sun can be seen without a telescope．1t was not until the invention of the telescope（望远镜）in the early l7th century，however，that systematic studies of sunspots could be undertaken．The great astronomer Galileo was among the first to make telescopic observations of sunspots．
Sunspots are regions of extremely strong magnetic fields（磁场）found on the sun's surface．A sunspot has a dark central core known as the umbra．The umbra is surrounded by a dark ring called the penumbra．where the magnetic field spreads outward．Sunspots appear dark because they are giving off less radiation．They are cooler than the rest of the sun's surface．
Sunspots are frequently observed in pairs or in paired groups．The members of a spot pair are identified as the leading spot and the following spot．They are identified by their position In the pair In terms of the direction in which the sun rotates（旋转）．
The number of sunspots at any one time varies．A large spot group may consist of as many as 10 groups and 300 spots across the sun．The number of spots changes in a fairly regular pattern called the sunspot cycle．The largest number occurs about every 11 years．At sunspot minimum, there are at most just a few small spots．
The average lifetime of an individual spot group is roughly one solar rotation．which is about 25 days．The most persistent large spots, however, can survive for two to three months．
41 Careful observations and systematic studies of sunspots
A were made by ancient astronomers．
B started in the early 17th century．
C were made by Galileo only．
D could be made without a telescope．
The passage is mainly concerned with______.
A．the components of sunspots
B．sunspots acting like planet-sized hurricanes
C．a better understand of the sun
D．sunspots and the hurricanes
根据下列材料请回答 41～45 题：
第 41 题 Careful observations and systematic studies of sunspots
Holiday shopping is an exciting and (36) thing to do for many people. They love the crowds, the time spent picking out that (37) gift for a loved one.
Then there are those of us who hate crowds. Robb Empson used to be one of those (38) holiday gift buyers. Not anymore. The 50-year-old man checked off his (39) gift list two weeks ago—shopping online. Knowing he doesn’t have to visit (40) during the crowded holiday season is a “wonderful feeling,” said Empson, who has been full of (41) online shopping for several years. This year, he spent about 700 dollars on a (42) holiday gifts from Amazon. com. (43) , Internet holiday sales grew 28 percent last year and 54 percent in 2000.
(44) .
Many are turning to online shopping as an alternative. The idea of shopping in your soft loose clothes you wear at home is pretty cool to those who hate shopping. The perfect gift is out there; one needs merely to surf the Web.
(45) .
With the click of a mouse, consumers can send flowers and gifts to distant relatives. Shopping online can be safe and convenient. Consumers need only to know the rules and to take steps to protect themselves. (46).
请在(36)处填上最佳答案.
Our social networks can【C2】______our behaviors and moods. Political scientist James Fowler of the University of California has studied these effects and previously found that obesity, smoking, and【C3】______happiness can spread through networks of people【C4】______based on their relationships.
Fowler【C5】______his study of a network of more than 8000 7th-to 12th-grade students and their sleeping and smoking【C6】______. He and colleagues【C7】______a web of connections between each student and his or her friends. In one of these friend webs, a gang of sleepless boys【C8】______the middle of the mess, where the most【C9】______kids landed--the so-called "cool" kids. The researchers found that the【C10】______central a teen landed on the map, the greater chance that he or she got less than 7 hours of sleep per night.
Drug use was also contagious(具传染性的), the team【C11】______. Each smoking friend increased the(78 that a student used marijuana(大麻)【C13】______42%. Both sleepless and drug-use contagions could still be felt four-degrees of separation【C14】______, influencing a friend of a friend of a friend's friend.
Most surprisingly, the researchers found a link between【C15】______of sleep and drug use.【C16】______a teen's friend slept less than 7 hours, her chances of using drugs went【C17】______by 19%. And that means that【C18】______sleeplessness spreads throughout a friend【C19】______, drug use spreads as【C20】______.
【C1】
A．bicycle
B．recycle
C．circle
D．cycle
