It seems to shine unchangingly, pouring out a constant light year after year. But the sun may not be nearly so stable as we suppose, It is now thought to move quickly and irregularly and change in long-term cycles, growing dimmer and then brighter with each passing year. Some even fear that its frequent changing behavior would have a great influence on the Earth’s climate.
The source of the sun’s inconstancy is magnetism. Professor William Livingston has developed new theories about its magnetic nature.
"We don’t yet know what causes sun spots, "he says, "but we now think they’re areas of high-level magnetism that come up from the sun’s interior. So strong is their magnetic pull that the highly ionized gas nearby is not able to transmit energy out." As a result these areas send out less heat and light and thus appear from Earth to be almost dark irregular surface patches.
Sun spot activity generally fluctuates in steady, 11-year cycled. Scientists have long formed the opinion that as the size and number of sun spots increased, the overall energy sent out by the sun would decrease. Indeed, recent studies confirmed it, revealing that during peak periods of sun spot activity, the Earth experiences a small drop that can be seen clearly in received solar energy.
Could such a small drop in energy have an effect here on earth Perhaps some scientists think the world temperature could fall by as much as 0.2 during periods of high solar magnetism... enough to cause significant fluctuations in weather patterns.
Which of the following statements is supported by the passage ______

A:The sun shines constantly and gives out the same amount of energy every year. B:The cause of the sun’s fluctuations is its loss of energy with each passing year. C:It is sure that the energy sent out by the sun will drop when more sun spots appear. D:Fluctuations in weather patterns are the results of the pull of gravity.

Passage 2
It seems to shine unchangingly, pouring out a constant light year after year. But the sun may not be nearly so stable as we suppose. It is now thought to move quickly and irregularly and change in long-term cycles, growing dimmer and then brighter with each passing year. Some even fear that its frequent changing behavior would have a great influence on the Earth’ s climate.
The source of the sun’ s inconstancy is magnetism. Professor William Livingston has developed new theories about its magnetic nature.
"We don’ t yet know what causes sun spots, "he says, "but we now think they ’ re areas of high level magnetism that come up from the sun’ s interior. So strong is their magnetic pull that the highly ionized gas nearby is not able to transmit energy out. "As a result these areas send out less heat and light and thus appear from Earth to be almost dark irregular surface patches.
Sun spot activity generally fluctuates in steady, 11-year cycled. Scientists have long formed the o pinion that as the size and number of sun spots increased, the overall energy sent out by the sun would de crease. Indeed, recent studies confirmed it, revealing that during peak periods of sun spot activity, the Earth experiences a small drop that can be seen clearly in received solar energy.
Could such a small drop in energy have an effect here on earth Perhaps some scientists think the world temperature could fall by’ as much as 0.2 during periods of high solar magnetism.., enough to cause significant fluctuations in weather patterns.

A:The sun shines constantly and gives out the same amount of energy every year. B:The cause of the sun' s fluctuations is its loss of energy with each passing year. C:It is sure that the energy sent out by the sun will drop when more sun spots appear. D:Fluctuations in weather patterns are the results of the pull of gravity.

Passage Two

A:The sun shines constantly and gives out the same amount of energy every year. B:The cause of the sun’s fluctuations is its loss of energy with each passing year. C:It is sure that the energy sent out by the sun will drop when more sun spots appear. D:Fluctuations in weather patterns are the results of the pull of gravity.

Please ______ that shop over there and I will go in and ask for directions.

A:pull in at B:pull at C:pull out at D:pull in

Mr. Smith's condition looks serious and it is doubtful if he will ______.

A:pull through B:pull up C:pull back D:pull out

We are so used to our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted. Because we can feel that things are heavy, we think of "weight" as being a fixed quality in an object, but it is not really fixed at all. If you could take a one-pound packet of butter 4,000 miles out from the earth, it would weigh only a quarter of a pound.
Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4,000 miles out into space The reason is this: All objects have a natural attraction for all other objects; this is called gravitational attraction. But this power of attraction between two objects gets weaker as they get farther apart. When the butter was at the surface of the earth, it was 4,000 miles from the center. When we took the butter 4,000 miles out, it was 8,000 from the center, which is twice the distance. If you double the distance between two objects, their gravitational attraction decreases four times (two times two). If you treble the distance, it gets nine times weaker (three times three) and so on.
So this is one of the first things we need to remember: that the weight of an object in space is not the same as its weight on the surface of the earth.
What about the weight of our pound of butter on the surface of the moon At the distance the pull of the earth is about 4,000 times smaller than it is here on the surface, so we can forget all about the earth-pull on our butter.
On the other hand, on the moon there will be an attraction between the butter and the moon, but the butter will weigh only about one-sixth as much as it does on the earth. This is because the moon is so much smaller than the earth. The amount of gravitational pull that a body produces depends on the amount of material in it. A packet of butter has a gravitational pull of its own; but this is very small in relation to the pull of something as large as the moon, or the earth, or the sun.

A:it is too small to have a gravitational pull of its own B:its pull is so small that we tend to ignore it C:its pull disappears in the presence of the earth’s gravitation D:it tends to melt and loses its gravitational pull

We do not feel the gravitational pull of a packet of butter because

A:it is too small to have a gravitational pull of its own. B:its pull is so small that we tend to ignore it. C:its pull disappears in the presence of the earth's gravitation. D:it tends to melt and loses its gravitational pull.

We do not feel the gravitational pull of a packet of butter because

A:it is too small to have a gravitational pull of its own. B:its pull is so small that we tend to ignore it. C:its pull disappears in the presence of the earth's gravitation. D:it tends to melt and loses its gravitational pull.