A computer is a
machine with a complex network of electronic circuits ( 电路) that operate
switches. The switches are capable of being in one of two possible states, that
is, on or off. The machine is capable of storing and dealing with numbers,
letters, and characters. The basic idea of a computer is that we can make the
machine do what we want simply by inputting signals that turn certain switches
on and turn others off. Computers are thought to have many
remarkable powers. However, most computers, whether large or small, have three
basic capabilities. First, computers have circuits for performing
arithmetic operations, such as: addition, subtraction, division, multiplication
and exponentiation. Second, computers have a means of communicating with the
user. After all, if we couldn't feed information in and get results back, these
machines wouldn't be of much use. However, certain computers (commonly
minicomputers and microcomputers) are used to control directly things such as
robots (机器人), medical instruments, etc. Some of the most common
methods of inputting information are to use magnetic tape, disks, and terminals.
The computer's input device reads the information into the computer.
For outputting information, two common devices used are a printer which
prints the new information on paper, or a CRT display screen which shows the
results on a TV-like screen. Third, computers have circuits
which can make decisions. The kinds of decisions which computer circuits can
make are not of the type: 'Who would win a war between two countries?' or
'Who is the richest person in the world?' Unfortunately, the computer can only
decide three things, namely: Is one number less than another? Axe two numbers
equal? and, Is one number greater than another?
单选题
A computer is, in a sense, simple in that it ______.
A. consists only of electronic circuits
B. can only store and deal with numbers, letters, and characters
C. performs its functions by means of operating switches
D. cannot work without signals
【正确答案】
C
【答案解析】[解析] (见第1段最后1句)
弄清题目和C)项里的几个短语的含义，有助于选择正确答案。
in a sense：在某种意义上
in that：因为
perform functions：起作用，发挥作用
by means of：用……方法、手段
operate switches：操纵开关
单选题
A computer can NOT ______.
A. perform arithmetic operations
B. communicate with the user
C. make a certain kind of decision
D. be of much use without input and output
【正确答案】
D
【答案解析】[解析] (见第2段4—5行)
D)项里的。input(输入)与原文“feed information in”同义。output(输出)与“gets results back”同义。
单选题
In the second paragraph, "remarkable powers" means ______.