精馏操作的依据是()的差异。A、相对挥发度 B、密度 C、质量 D、体积

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问题:

精馏操作的依据是()的差异。

A、相对挥发度

B、密度

C、质量

D、体积

考点:环己酮车间环己酮车间题库
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如下图,足够长的粗细均匀的直玻璃管中,有一段15cm的水银柱,竖直放置时空气柱的长度为60cm,外界大气压强为75cm水银柱,现将玻璃管旋转,旋转过程中水银柱没有流出:

1)、转至水平时,管内空气柱的长度是多少?2)、转至开口竖直向下,管内空气柱的长度是多少?

题型:单项选择题

It is a wonderful morning,as I write this:hot,but without being too hot. Outside my window,I can see the sunniest sky of the year reflected in a huge natural expand of water. It is the kind of sun that makes you well aware of summer’s temporary nature —a reminder that if I am ever to go around to book this year's holiday,time is running out .

It is now close to four years since I last took a holiday. This is because I have come to the conclusion, over the course of my adult life, that I am not very good at it. You might say this sounds like saying you are not very good at drinking tea or listening to music.  What could possibly be difficult about the natural act of putting your working life on hold for a couple of weeks and going somewhere to do nothing?

So what is my problem? On the surface, I'm probably a bit of homebody. And I just find the pressure of being on holidy too severe: it always feels like having a gun held to my head and being forced to have fun. Somehow, packing a carefully itemized list of possessions and meeting a scheduled flight has none of the excitement of suddenly deciding to take a day off and driving somewhere for the fun of it.

Thankfully, I am not alone. This summer, most of my friends have decided not to have a break. And a recent survey highlighted the downside(负面)of holidays, with the results shoeing that nearly two thirds of people found that the calming effects of a holiday wore off within 24 hours, as stress levels returned to normal. And this year's the Idler magazine published its book of awful holidays .Here you will find a list of the five most ecologically--damaging vacations it's possible to take, along with 50 horrible holidays experiences voted for on the idler website. Over the last decade, The Idler has become well known for promoting the idea of an easy, lazy life. The leisure(休闲)industry might seem an unlikely target of its criticism, but Dan Kienan, the book's editor, says that he was flooded with entries from readers for his list of awful holidays.

小题1:According to the first paragraph We can know that the writer        .

A. has a strong desire to book a holiday

B. wishes that the weather would change

C. finds it is too late to enjoy the sunshine

D. realizes it’s time to decide whether to go on a holiday小题2:What can be inferred from the sentence underlined in the passage?

A. people may find the man unbelievable

B. People think traveling is not so easy an act as drinking tea

C.The writer often regrets not taking a holiday.

D. The writer doesn't like drinking tea or listening to music小题3:The reason why the writer dislikes going on holidays is that      .

A. it usually takes too much time

B. he is tired of making preparations too much for holidays

C. it is far less enjoyable than breaks planned in advance

D. he feels embarrassed when other people are having fun but he isn't小题4:We can learn from the survey that a lot of people         .

A. pretend to enjoy their holiday

B. fail to relax while they are on holiday

C. feel that the benefits of going on holidays are limited

D. have made the some decision as the writer and most of his friends小题5:The writer takes the book of Awful Holidays as an example to             .

A. damage the reputation of the magazine

B.prove his idea to be more popular than expected

C. indicate that his dislike of holidays is widely shared

D. foucs entirely on bad personal experiences of holidays

题型:单项选择题

患者女性,30岁。干咳,咳声短促,痰中有时带血,色鲜红,午后手足心热,皮肤干灼,口干咽燥,胸部隐隐闷痛。舌边尖红,苔薄,脉细数。应诊为何型肺痨()

A.阴虚火旺

B.气阴两虚

C.肺阴亏损

D.肺肾同病

E.阴阳两虚

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舟骨结节及远端骨折需固定()

A.2周

B.2~4周

C.4~8周

D.10~12周

E.3个月以上

题型:单项选择题

哪一个不属于稳健型客户期待的服务方式()

A.简单

B.立刻处理问题

C.不需要多余的服务

D.创造惊喜

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