9．An optical computer is a computer that uses electricity i. e. electrons, to manipulate, store and
虚拟存储器是由主存和()组成。
A. 辅存
B. cache
CD-ROM
D. 内存
7．One of the drawbacks of a computer is that it cannot he used as a recreational device.
We can infer that ______.
A. there will be no distinction between micros and mainframes in the future
B. a future computer can use several CPUs to work for it at the same time
C. the fifth generation computer will be produced within 2 years
D. electronic computers will soon be out of date
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