Section B Directions : There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice. Passage One Questions 51 to 55 are based on the following passage. It is very hard to imagine what life would be like without memory. The meanings of everyday perceptions, the basis for the decisions we make, and the roots of our habits and skills are to be found in our past experiences, which are brought into the present by memory. Memory can be defined as the capacity to keep information available for later use. It not only includes “remembering” things like arithmetic or historical facts, but also involves any change in the way an animal typically behaves. Memory is involved when a rat gives up eating grain because he has sniffed( 嗅出 ) something suspicious in the grain pile. Memory exists not only in humans and animals but also in some physical objects and machines. Computers, for example, contain devices for storing data for later use. It is interesting to compare the memory storage capacity of a computer with that of a human being. The instant access memory of a large computer may hold up to 100,000 “words” – string of alphabetic or numerical characters—ready for instant use. An average U.S. teenager probably recognizes the meaning of about 100,000 words of English. However, this is but a fraction of the total amount of information that the teenager has stored. Consider, for example, the number of faces and places that the teenager can recognize on sight. The use of words is the basis of the advanced problem-solving intelligence of human beings. A large part of a person’s memory is in terms of words and combinations of words. But while language greatly expands the number and the kind of things a person can remember, it also requires a huge memory capacity. It may well be this capacity that distinguishes humans, setting them apart from other animals.