单项选择题
By saying "... owners of well over half of all World Wide Web sites have set up home without fitting locks to their doors" ( Line 3, Para. 2), the author means that ()
A.many sites are not well-protected B.those happy times appear still to be with us C.there simply wasn't any crime to worry about D.hackers try out tricks on an Internet site without actually breaking in
单项选择题 Which of the following is true about Bille's lenses()
单项选择题 According to Bille, with the new lenses the wearer's vision ()
单项选择题 Individualized contact lenses (Line 6, Para. 2) are lenses designed ()