为了提高浮选效果，可向污水中投入少量的浮选剂，以降低污水的（）。A、表面张力 B、粘

发布时间：2017-06-25 10:24 │ 来源：www.tikuol.com

题型：单项选择题

问题：

为了提高浮选效果，可向污水中投入少量的浮选剂，以降低污水的（）。

A、表面张力

B、粘度

C、密度

D、含铁量

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现有一种人工制成的膜，为探究淀粉和碘能否透过该膜，用铁架台、烧杯、用这种膜做成的袋、细棉线、1%的淀粉溶液、稀碘溶液等用品，设计如图的实验装置：

（1）碘能使淀粉变蓝，这是碘的______性质．（填“物理”或“化学”）

（2）如果实验结果是袋内外液体均不变蓝，则表明淀粉和碘均不能透过该膜；如果袋内液体变蓝，袋外液体不变蓝，则表明______．

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完形填空。

     Around the world, people have different ideas about what good manners are.
     When you go to restaurants in different parts of the world, it's  1 to know the right and wrong things
to do. For example, in China it's OK to  2 a lot of noise in a restaurant. In fact, if a restaurant isn't 3 or lively,
you may think there's something wrong with it. However, in many western countries, restaurants are quiet
places. If a table is too loud, other people who are eating there might even  4  to the owner of the restaurant.
    Paying the bill  5 also different from country to country. In China, one person usually pays  6 everybody.
In western countries, one person pays if he or she is entertaining clients (宴请宾客), but  7 friends eat together,
they usually share the cost. This is called "Going Dutch (均摊费用)". Also, when westerners pay the bill, they
usually leave some money for the  8 .This is called"leaving a tip (小费)". Leaving a tip is thought to be polite.
In the US, it's  9 to leave tips of 10％,15％,or 20％ of the bill, which is decided by how good the service is.
Good waiters can make a lot of money!
     The way people eat food is different in the world, but you can  10 the same kind of food in many
countries. Chinese and Italian food, for example, are popular all over the world.

( )1. A. popular
( )2. A. cause
( )3. A. noisy
( )4. A. shout
( )5. A. are
( )6. A. on
( )7. A. until
( )8. A. gatekeeper
( )9. A. terrible
( )10. A. invent

B. difficult
B. keep
B. noise
B. explain
B. is
B. for
B. when
B. seller
B. common
B. find

C. important
C. make
C. lucky
C. complain
C. be
C. in
C. unless
C. waiter
C. serious
C. prefer

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题型：单项选择题

在下列四组线段中，能组成直角三角形的是（　　）

A．a=2，b=3，c=4

B．a=1，b=2，c=3

C．a=9，b=15，c=12

D．a=3，b=6，c=9

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肾上腺疾病分为肾上腺皮质疾病和髓质疾病两类。

肾上腺皮质疾病不包括（）。

A.肾上腺皮质功能亢进

B.肾上腺皮质功能不全

C.原发性醛固酮增多症

D.库欣综合征

E.节细胞神经瘤

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题型：单项选择题

我党历史上生死攸关转折点的会议[ ]

A．中共一大

B．遵义会议

C．十一届三中会议

D．中共七大

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