离子方程式CO32- + 2H+ = H2O + CO2↑中的CO32-代表的物质可以是( )
A.CaCO3
B.NaHCO3
C.Na2CO3
D.BaCO3
答案:C
“新经济政策”规定,中小企业和国家暂时无力兴办的企业,允许本国和外国资本家经营。这表明( )。
A.苏俄开始着眼于解决经济困难
B.苏俄充分利用外资发展民族企业
C.苏俄开始利用市场和商品货币关系发展生产以向社会主义过渡
D.苏俄决定实行改革开放
Melissa and LoveLetter made use of the trust that exists between friends or colleagues. Imagine receiving an (46) from a friend who asks you to open it. This is what happens with Melissa and several other similar E-mail (47) . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages (48) .
A. cracker B. user C. customer D. client
As administrators seek to block dangerous email attachments through the recognition of well-known (49) , virus writers use other extensions to circumvent such protection. Executable (.exe)files are renamed to. bat and. cmd 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 (50) access to your network.