試題詳解

21. By saying “... owners of well over half of all World Wide Web sites have set up home without fitting locks to their doors" (Lines 3-4, Para. 2), the author means that _____.
(A) those happy times appear still to be with us
(B) there simply wasn't any crime to worry about
(C) many sites are not well-protected
(D) hackers try out tricks on an Internet site without actually breaking in