题目内容：

    Today's personal computers are very different from the huge machines that were born during World War II-and the difference isn't only in their size. By the 1970s, these early PCs could not perform many of the tasks that today's computers can. Users could only do mathematical calculations(数学计算) and play simple games. Today PCs are used in many different kinds of ways. At home and at work, we use our PCs to do almost everything. It is nearly impossible to imagine modern life without them.

The earliest computers were not "personal" in any way: They were large and expensive, and they required a team of engineers and other experts to keep them running. One of the first and most famous of these, the Electronic Numerical Integrator Analyzer and Computer (ENIAC),  was built at the University of Pennsylvania. ENIAC cost ﹩500, 000, weighed 30 tons and took up nearly 2, 000 square feet of floor space.

ENIAC and other early computers proved that the machines were worth so much money, space and manpower they needed. For example, ENIAC could solve in 30 seconds a problem that could take a team of human "computers" 12 hours to complete. At the same time, new technologies were making it possible to build smaller computers.

But one of the most important of the inventions that make way for the PC revolution was the microprocessor(微处理器). Microprocessors were the size of a nail. They could run the computer's programs, remember information and manage data(数据) all by themselves.

These new ideas made it cheaper and easier to produce computers than ever before. As a result, the smaller, cheaper "microcomputer"-soon known as the "personal computer"-was born. Today, portable computers, smart phones and ipads allow us to have a PC with us wherever we go.

1.What's mainly talked about in the first paragraph? ______

A.An even more relaxing lifestyle without PCs.

B.PCs can be made full use of to do everything.

C.Differences between modern and early PCs.

D.The difficult situation of PCs being born.

2.What do we know about the earliest computers? ______

A.It was easy to control them. B.They took up too much room.

C.Nobody could afford one. D.They were built by universities.

3.Why does the writer take ENIAC for example? ______

A.To predict high technology will make computers smaller.

B.To show computers are really smarter than human beings.

C.To explain why computers could deal with any problem.

D.To prove spending money on early computers was meaningful.

4.Which of the following makes the biggest contribution to microcomputers? ______

A.Microprocessors. B.Programs. C.Money. D.Imagination.