With a tremendous roar from its rocket engine, the satellite is sent up into the sky. Minu

tes later, at an altitude of 300 miles, this tiny electronic moon begins to orbit about the earth. Its radio begins to transmit a staggering amount of information about the satellite's orbital path, the amount of radiation it detects, and the presence of meteorites. Information of all kinds races back to the earth. No human being could possibly copy down all these facts, much less remember and organize them. But an electronic computer can.

The marvel of the machine age, the electronic computer has been in use only since 1946. It can do simple computations—add, subtract, multiply, and divide—with lightning speed and perfect accuracy. It can multiply two 10-digit numbers in 1/1, 000 second, a problem that would take an average person five minutes to do with pencil and paper. Some computers can work 500, 000 times faster than any person can.

Once it is given a program, that is, a carefully worked-out set of instructions devised by a technician trained in computer language, a computer can gather a wide range of information for many purposes. For the scientist it can get information from outer space or from the depths of the ocean. In business and industry the computer prepares factory inventories, keeps track of sales trends and production needs, mails dividend checks, and makes out company payrolls. It can keep bank accounts up to date and make out electric bills. If you are planning a trip by plane, the computer will find out what route to take and what space is available.

Why does the author regard the electronic computer as the marvel of the machine age？

A．Because electronic computers are rare.

B．Because people know little about electronic computers.

C．Because electronic computers can do much more kinds of work that human beings can't.

D．Because electronic computers have been widely suspected.