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问题 填空题

两地相距93千米，甲乙两人骑自行车同时从两地相对出发，经过3小时相遇．相遇后又同时行使2小时，甲乙两人相隔______千米．

答案

93÷3×2，

=31×2，

=62（千米）；

答：甲乙两人相隔62千米．

故答案为：62．

选择题

读四种自然灾害持续时间示意图3，回答13～14题。

小题1:①②③④四种灾害分别是

A．火山、地震、旱灾、洪涝

B．地震、火山、旱灾、洪涝

C．旱灾、洪涝、地震、火山

D．地震、火山、洪涝、旱灾小题2:下列关于自然灾害特点的叙述，正确的有

①灾害的发生没有明显的地域性特点

②灾害引发泥石流，体现灾害的关联性特点

③灾害的发生，体现自然灾害具有突发性的特点

④灾害的发生，体现自然灾害具有渐发性的特点

A．①②

B．③④

C．①③

D．②④
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单项选择题

Melissa and LoveLetter made use of the trust that exists between friends or colleagues.Imagine receiving an （） from a friend who asks you to open it. This is what happens with Melissa and several other similar email （） . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages （） . As administrators seek to block dangerous email attachments through the recognition of well-known （） , 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 （） access to your network.

web pages （） .

A．memory

B．caches

C．ports

D．registers
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