理工类B级辅导资料：专项练习Agitated sunspots
If the lights in your house keep flicking， blame frequent sunspots.
A sunspot is actually charged particles flying at the speed of 3 million kilometers an hour out of the surface of the sun to form sun storms.
__1__.
The earth， which is directly energized by the sun， is influenced by sun storms in a number of ways.
__2__. Wireless short-wave communication， which depends on the waves reflection against this layer of atmosphere， is likely to be jammed. It is said that mobile phone communication may be affected too.
__3__. According to a research conducted by the Russian scientists from 1957 to 1960， the frequency of earthquake can be linked to the movement of the sunspots.
Though little research has been carried out about how exactly the sunspot will negatively harm the health of the people， a paper published by a North Korea observatory says that sun storms may cause an increase in the incidence of heart disease and skin disease.__4__.
Besides， the nervous system is also affected， and traffic accidents are more frequent when sunspots are active.
It is hard to say when the sunspots are most violent during their active year but generally one active period is believed to last possibly eight days. Not long ago there were two violent sun storms breaking out， which seriously affected mobile phone communication， etc， in many parts of the world. __5__.
A. Every 11 years， the sun， as its energy accumulate inside up to a certain point， will send out streams of charged particles， which affect the earth in different ways.
B. One is that the magnetic field of the earth is much disturbed because of the suns interference in the inosphere， which is 80 to 500 kilometers above the earth.
C. Scientists also say that the active movement of the charged sun storm also has effects on earthquakes.
D. So， scientists warn that people going outdoors should be careful to protect their exposed skin and eyes with clothes， umbrellas and sunglasses from the strong sunlight rich in ultraviolet rays.
E. Ionosphere is high above the earth and so people on the earth are comparatively less affected by it.
F. But the communication situation in each case returned to normal in about 24 hours.
标准答案： F，E，D，C，B