单选题 .  .We are not about to enter the Information Age, but instead are rather well into it." Present predictions are that by 1990, about thirty million jobs in the United States, or about thirty percent of the job market, will be computer-related. In 1980, only twenty-one percent of all United States high schools owned one or more computers for student use. In the fall of 1985, a new survey revealed that half of United States secondary schools have fifteen or more computers for student use. And now educational experts, administrators, and even the general public are demanding that all students become "computer literate". By the year 2000 knowledge of computers will be necessary in over eighty percent of all occupations. Soon those people not educated in computer use will be compared to those who are print illiterate today.
    What is "computer literacy"? The term itself seems to imply some extent of "knowing" about computers, but knowing what? The current opinion seems to be that this should include a general knowledge of what computers are, plus a little of their history and something of how they operate.
    Therefore, it is vital that educators everywhere take a careful look not only at what is being done, but also at what should be done in the field of computer education. Today, most adults are capable of utilizing a motor vehicle without the slightest knowledge of how the internal combustion engine works. We effectively use all types of electrical equipment without being able to tell their histories or to explain how they work. Business people for years have made good use of typewriters and adding machines. Yet few have ever known how to repair them. Why, then, attempt to teach computers by teaching how or why they work?
    Rather, we first must concentrate on teaching the effective use of the computer as the tool is, "Knowing how to use a computer is what's going to be important. We don't talk about 'auto-mobile literacy'. We just get in our cars and drive them."1.  By 1990, the number of jobs having something to do with computers in the United States will be ______.