●Melissa and Love Letter made use of the trust that exists between friends or colleagues.Imagine receiving an (66) from a friend who asks you to open it.This is what happens with Melissa and several other similar email (67) .Upon running, such worms usually proceed to send themselves out to email addresses from the victim's address book,previous emails, web pages (68) .

●Network (71) has full rights and permissions to all resources on a network.

●Note：Make (72) regularly in data processing.

●During the last few years，it has been realized that maintenance of programs is more expensive than development,so reading of programs by humans is as important as (73) them.

●In recent years，TCP／IP has also begun to be used by telephone companies to provide faster,cheaper telephone (74) .

●C++is used with proper (75) design techniques.