The web is an information space.Human beings have a lot of mental machinery for manipulating，imaginin9，and finding their way in spaces.URIs are the (1)in that space.
Unlike web data formats，where HTML is an important one，but not the only one，and web pmto- cols，where HTTP has a similar status，there is only one Web (2)technology：URIs. Uniform Resource Identifiers(URIs，aka URLs)are short strings that (3)resources in the web： documents，images，downloadable files，services，electronic mailboxes，and other resources.They make resources(4)under a variety of naming schemes and(5)methods such as HTTP，FrP，and Interact mail addressable in the same simple way.They reduce the tedium of”log in to this server.then issue thi{ magic command…”down to a single click.
It is an extensible technology：there are a number of existing addressing schemes，and more may be incorporated over time.
(1)A、identifiers
B、strings
C、machines
D、points
(2)A、accessing
B、naming/addressing
C、communicatin9
D、searching
(3)A、nanle
B、access
C、identify
D、find
(4)A、available
B、avail
C、reachable
D、necessary
(5)A、explorer
B、download
C、access
D、browse