单项选择题

Today, the world wide web can be used both to search information and to make it (31) to others. Information (32) on webpages is viewed by (33) of browser. The sources of information linked in this way can be located on any computer (34) is also part of the web. Each information source may be linked to an (35) number of other webpages. Hypertext and hyper- links allow users (36) as receivers of in- formation to (37) from one source of in- formation to another, deciding for themselves which information they wish to (38) .to their browser and which links they want to (39) The addresses of (40) can be found by using the hundreds of search engines Which provide (41) to databases which hold information on them. Once a webpage has been found, hyperlinks may point (42) other places of interest on the web. Addresses of webpages also appear in other more (43) media, such as magazines, newspapers and television programs, and on posters. Webpages, in their (44) facilitate access to information made available by other (45) of media, for example, collections held in libraries. Most webpages offer interactive opportunities which go (46) merely allowing visitors freedom as to when and how they visit a page. (47) can be kept formal via a questionnaire which can be filled (48) , or informal by providing an address for e-mail or even by installing a digital guest book for comments left for other users to read. (49) all web- pages are protected so that unauthorized visitors cannot make unsolicited changes to them, it is also possible to (50) access to pages on the internet to those holding a password.