下列分离物质方法不正确的是（） A．用过滤的方法除去粗盐_爱下问搜题

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问题选择题

下列分离物质方法不正确的是（　　）

A．用过滤的方法除去粗盐水中悬浊的泥沙

B．用蒸馏的方法将自来水制成蒸馏水

C．用酒精萃取的方法将碘水中的碘富集

D．用淘洗的方法从沙里淘金

答案

A．过滤可以把不溶于液体的固体物质和液体分离，用过滤法分离混合物时主要应该考虑物质是否能够溶于水，泥沙不溶于水，用过滤的方法除去粗盐水中悬浊的泥沙，故A正确；

B．自来水中含有一些难以挥发的无机盐类物质，可通过蒸馏的方法制取蒸馏水，故B正确；

C．酒精和水互溶，不能用作萃取溴水中溴的萃取剂，故C错误；

D．淘洗是依靠金和沙子的密度不同而进行分离，在淘洗过程中，较轻的沙子易被水流带走，而留下较重的金，故A正确；

故选C．

单项选择题 A3/A4型题

患者女性，50岁，因腹痛、呕吐、停止排气排便就诊，尿量600ml/d。查体：血压100/70mmHg，皮肤干燥，眼球下陷，腹胀，肠鸣音亢进，白细胞12×10⁹/L，血清钾3.7mmol/L，血清钠128mmol/L，血清氯101mmol/L。

患者经治疗后症状体征改善，以下哪项指标尚不正常（）

A.血清氯110mmol/L

B.尿量50ml/h

C.白细胞9.8×10⁹/L

D.血清钠138mmol/L

E.血清钾3.6mmol/L

单项选择题

Melissa and LoveLetter made use of the trust that exists between friends or colleagues. Imagine receiving an (16) from a friend who asks you to open it. This is what happens with Melissa and several other similar email (17) . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages (18) .

A. namesB. cookiesC. software D. extensions

As administrators seek to block dangerous email attachments through the recognition of well-known (19) , 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 (20) access to your network.