阅读理解。
We often hear people say, "I have a good memory for things like that" or "I can remember
names". But do you know memory is the single most important thing and it has played a very
important part?
For early men, there were dangerous all around them-bad weather, wild animals. The keys
to keep on living lay in man's ability to remember these dangers and the ways he had dealt with
them in the past. In order for memories to be stored, the human brain became more complex.
And as man learned how to deal with them, he became civilized (文明).Surprisingly, scientists
today understand little about memory and how it works. They havenot yet found a way to open
up the brain and observe its function without destroying it. Perhaps there are two types of
memory: short-term and long-term. Short-term refers to those facts that stay with us for a few
seconds to a few hours. For instance, when you stay at a hotel, you remember the room number
and forget as soon as you leave. Long-term memory, on the other hand, means you remember
things for a long period of time. If you spend your honeymoon in a particular hotel, it's likely that
you'll remember your stay quite clearly.
Scientists also believe that a short-term memory can become a long-term memory through
consolidation (巩固). A lot of chemical and physical changes take place in the part of the brain.
Although the human brain weighs three pounds, it contains 30 billion nerve cells (神经细胞) acting
like a computer. When those changes strengthen the links (联系) in certain nerve cells, a though
becomes a part of the long-term memory.
1. According to the author, without the development of man's memory there would be _____. [ ]
A. no modern world
B. no recorded history
C. no animals
D. no dangers
2. Scientists' knowledge about the function of brain is _____.[ ]
A. interesting
B. not enough
C. great
D. encouraging
3. Short-term memory can change into long-term memory on condition that _____. [ ]
A. memory is good
B. it acts like a computer
C. people do more exercise
D. the links in nerve cells are strengthened by certain changes
4. So far the great discovery scientists have made about the function of brain is _____. [ ]
A. the weight of brain
B. two types of memory
C. 30 billion nerve cells
D. chemical and physical changes
