阿斯匹林是常用的退热、止痛药．实验证明：阿斯匹林稀溶液喷洒到_爱下问搜题

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问题填空题

阿斯匹林是常用的退热、止痛药．实验证明：阿斯匹林稀溶液喷洒到菜豆、玉米上，这些作物耐旱能力增强，并能加速开花获得高产，阿斯匹林（乙酰水杨酸）的化学式为C₆H₄COOH（OCOCH₃），阿斯匹林中各元素质量比C：H：O=______，氧元素的质量分数为______%．

答案

（1）根据阿斯匹林（乙酰水杨酸）的化学式为C₆H₄COOH（OCOCH₃）可写成C₉H₈O₄，则碳、氢、氧三种元素的质量比为（12×9）：（1×8）：（16×4）═27：2：16，故答案为：27：2：16；

（2）阿司匹林的化学式为C₉H₈O₄，氧元素的质量分数为：

16×4

12×9+1×8+16×4

×100%═35.6%，

故答案为：35.6

单项选择题

Melissa and LoveLetter made use of the trust that exists between friends or colleagues. Imagine receiving an (6) from a friend who asks you to open it. This is what happens with Melissa and several other similar email (7) . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages (8) .

As administrators seek to block dangerous email attachments through the recognition of well-known (9) , 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 (10) access to your network.

10（）

A.cracker

B.user

C.customer

D.client

判断题

在期货市场上，套期保值者是为了实物交割，投机者是为了获得风险收益。( )