【正确答案】 D

【答案解析】[解析] 5-8
During the past several years，many new uses of television sets have been introduced．Video cassette recorders，video games，cable TV，and home computers are becoming popular accessories for the home TV．The videodisc is the most recent and perhaps the most important of new attachments．
A videodisc looks like an ordinary record，but it reproduces pictures and sounds．It is designed to play back programs that have been recorded on it. The manufacturers record movies，concerts，and educational programs on the discs．
A videodisc is made of plastic．Its surface is covered with tiny pits that wind around the disc in a coil． The Size and arrangement of the pits form a code that represents the recorded pictures and sounds．As the disc spins on the disc layer，the player reads the code and translates it into a TV signal which is then shown on the TV screen．
Manufacturers began developing videodiscs in the 1970s．Videodiscs and players have been available for home use since December 1978，and their manufacturers hope that they will become as popular as records and record players．Home entertainment，however，is not the only use for videodiscs．Some companies are developing videodisc system to store computer information and record visual computer programs．Home computers may even be used with video players in the future．