若一个三角形的三边长分别为1、a、8(其中 a为正整数),则以a-2、a、a+2为边的三角形的面积为( )。
24
依法应当登记的非机动车,经公安机关交通管理部门登记后,方可上道路行驶。( )
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) . As administrators seek to block dangerous email attachments through the recognition of well- known (69) , virus writers use other extensions to circumvent such protection. Executable (.exe) files are renamed to . bat and . cnd plus a whole list of other extensions and will still run and successfully infect target users. Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which, while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the (70) access to your network.
A.attachment
B.paeket
C.datagram
D.message