A、The saving of time and money. B、The wide use of word processors. C、The decreasing number of secretaries. D、The use of computer

Without most people realising it, there has been a revolution in office work over the last ten years. Before that time, large computers were only used by large, rich companies that could afford the investment. With the advancement of technology, small computers have come into the market, which are capable of doing the work that used to be done by much larger and expensive computers, so now most smaller companies can use them.
    The main development in small computers has been in the field of word processors, or WPS as they are often called. 40% of British offices are now estimated to have a word processor and this percentage is growing fast. There are many advantages in using a word processor for both secretary and manager. The secretary is freed from a lot of daily work, such as retyping letters and storing papers. He or she can use this time to do other more interesting work for the boss. From a manager’s point of view, secretarial time is being made better use of and money can be saved by doing daily jobs automatically outside office hours.
    But is it all good? If a lot of daily secretarial work can be done automatically, surely this will mean that fewer secretaries will be needed. Another worry is the increasing medical problems related to work with visual display units. The case of a slow loss of sight among people using word processors seems to have risen greatly. It is also feared that if a woman works at a VDU for long hours, the unborn child in her body might be killed. Safety screens to put over a VDU have been invented but few companies in England bother to buy them.
    Whatever the arguments for and against word processor, they are a key feature of this revolution in office practise.
Questions 20 to 22 are based on the passage you have just heard.
20. Why didn’t smaller companies use large computers ten years ago?
21. What is the main feature of the revolution in office work over the last ten years according to the passage?
22. What is implied about the result of using word processors in the passage?