题目内容：
共用题干第一篇
TapeStore: A New Tape Storage System
TapeStore is a new kind of tape storage system which can store up to 6, 000 computer
tapes.No other tape storage system can hold as many computer tapes as TapeStore. The
tapes look exactly like video cassettes.Many hundreds of data files can be stored on each
tape,up to a maximum of 500 million bytes（字节）of data. If you stored the same amount
of information on paper,you would need nearly 4. 5 billion printed pages.
The machine is a tall black box with a mechanical arm.The machine is 2.5 metres high
and 3.0 metres wide,This is how it works.Each tape has a code printed on it.You feed
the code number into TapeStore,which then looks for the code.As soon as TapeStore
locates the code,the arm reaches in and pulls out the tape.
The system is very fast.It takes the mechanical arm about 1 0 seconds to find the tape
it is looking for. The machine then searches the tape to extract（提取）the required file,
and this takes less than a minute.A human technician would have to locate and remove the
tape by hand,and could take at least an hour to find the right file on the tape.
Some of the world's biggest companies,including banks,insurance companies,
airlines,telephone companies,utilities and computer centres,have bought the system.
They like it particularly because the system guarantees the security of their data.
TapeStore was originally developed in Canada and is now being marketed worldwide.
In Europe alone,750 have already been installed at a cost of 480,000 dollars each.
The word"marketed" in the last paragraph can be replaced by
A:installed.
B:used.
C:promoted.
D:designed.
参考答案：