冷原子吸收分光光度法测定固体废物样品和城市生活垃圾样品中总汞时,经高锰酸钾-过硫酸钾

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问题:

冷原子吸收分光光度法测定固体废物样品和城市生活垃圾样品中总汞时,经高锰酸钾-过硫酸钾消解后的试样临测定前需滴加盐酸羟胺溶液,此操作中应注意什么?

考点:环境监测上岗考试环境空气采样环境空气采样题库
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我国卫生部颁布《精子库管理办法》的年份是( )

A.2001年
B.2003年
C.1993年
D.1997年

题型:问答题 简答题

对从外周血管行左心腔超声造影原理的叙述,下列哪一项是正确的()

A.经股动脉注入造影剂

B.造影剂经腔静脉直接进入左心

C.造影剂微气泡的直径<10μm

D.造影剂微气泡直径>10μm

E.必须用白蛋白包裹空气的造影剂

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I’m very tired, ______ I need to have a good rest.   [ ]

A. because      

B. so          

C. but          

D. then

题型:问答题 简答题

阅读下面的短文,然后按照要求写一篇150词左右的英语短文。

The Nigerian postal service has witnessed a reduction in the number of letters sent, especially by individuals, due to the alternatives of email and text.

“People prefer these over letters, because of the speed, although letters serve many purposes, other than conveying of messages", said Barry Varley Tipton, principal of Cherry Field College.

But some people think that the vanishing(逐渐消失的) art of letter writing has grave (严重的) consequences for students, teachers, the economy, society and the beauty of reading from loved ones, because letters in those days usually had a variety of styles .

A lover of letters writing, Hajiya Aisha refers to the occasions she has seen people enraged, because their connections at a cyber cafe took 56 seconds rather than the usual 36 hours. She says, “Although letters are slow, waiting for something good is not wholly a bad thing. Nothing beats a hand written letter.”

"When I was a graduate studying overseas twenty five years ago, my mother wrote to me daily. It was wonderful to receive those letters. They often said nothing more than everyone was thinking of me. I continue this tradition with several friends who are scattered worldwide. Hand written letters show the love that we have for family and friends. Email cannot replace the smile of actually getting the letter. The warm, sincere thank- you note, or the sweetly scented love letter we usually received and sent in those days is irreplaceable" she said.

Will electronic age stamps replace letters? Hopefully not, since it takes with it a culture rich in colour, history, and communication. Letters, like bits of ourselves, deserve to be stored away for future readers, giving them insight into details as small as the price and pattern of stamps, and as great as personal insights exchanged long ago.

【写作内容】

1. 以约30词概括以上短文的主要内容:

2. 然后以约120个词以“Will written letters die out ?”为主题写一篇短文,并包括如下要点:

(1)有些人认为用手机收发短信和用因特网收发邮件更加方便快捷,写信很费时间

(2)有些人喜欢和朋友或家人写信

(3)你的观点

【写作要求】

1. 你可以使用实例或其他论述方法支持你的论点,也可以参照阅读材料的内容,但不得直接引用阅读材料中的句子

2. 作文中不能出现真实姓名和学校名称

【评分标准】

概括准确、语言规范、内容合适,篇章连贯。  (请在答题纸上作答)

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