What is a black hole? Well, it is difficult to answer the question, as the terms we would normally use to describe a scientific

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问题    What is a black hole? Well, it is difficult to answer the question,
as the terms we would normally use to describe a scientific phenomenon 【M1】______
are adequate here. Astronomers and scientists think that a black hole is 【M2】______
a region of space which matter has fallen and from which nothing can 【M3】______
escape—not even light. But we can’t see a black hole. A black hole 【M4】______
exerts a strong gravitational pull and yet it has no matter. It is only space—or
thus we think. How can this happen? 【M5】______
   The theory is that some stars explode when their density increases to
a particular point: they "collapse" and sometimes a supernova occurs.
The collapse of a star may produce a "White Dwarf" of a "neutron star"—
a star which matter is so dense that if continually shrinks by the force of 【M6】______
its own gravity. But if the star is very large, this process of shrinking may be
so intense that a black hole results in. Imagine the earth reduced to the 【M7】______
size of a marble, but still having the same masses and a stronger 【M8】______
gravitational pull, and you have some ideas of the force of a black hole. 【M9】______
And no matter near the black hole is sucked in. 【M10】______
【M9】

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答案ideas—idea

解析 “idea”在表达“印象”时,为不可数名词,不可以用复数。
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