对原始统计资料的要求是（）。 A.及时收集完整、准确的资料 B._爱下问搜题

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问题单项选择题 B1型题

对原始统计资料的要求是（）。

A.及时收集完整、准确的资料

B.综合资料

C.计算分析资料，剔除不合格资料

D.设计、收集资料，整理资料，分析资料

E.完整、准确、及时，要有适当的数量、代表性和对比条件

答案

参考答案：E

阅读理解

阅读理解。

A Simple Scientific Experiment

Below is a description of a single scientific experiment . It shows us how iron reacts ( 反应) with air and
with water.
Aim : To find out if iron rusts( 生锈) (a) in dry air ; (b) in water that has no air in it ( air- free water) ; (c)
in ordinary water.
Materials : 3 clean iron nails ( 铁钉) ; test tubes ; test tube holder ; cotton wool ; oil ; Bunsen burner.

Iron in dry air
Method
(1)Put some iron nails at the bottom of a test tube.
(2)Push some cotton wool down the tube.
(3)Leave the tube for one week.
Result
After one week, the nails have not rusted.
Conclusion
Iron does not rust in dry air.
Iron in air-free water
Method
(1)Half-fill a test tube with water.
(2)Boil the water for three minutes.( This makes sure
there is no air in the water.
Put two or three clean nails in the water.

(4)Add some oil to the water. ( This will keep
air out of the water.)
(5) Leave the tube for one week.
Result
The nails do not rust in the tube with air-free
water.
Conclusion
Iron does not rust in air- free water.
Iron in ordinary water
Method
(1)Half -fill a test tube with water and add two
or three clean nails.
(2)Leave the tube for one week.
Result
The nails rust in the tube with ordinary water.
Conclusion
Iron rusts in ordinary water.

1. In the first part of the experiment the cotton wool is most probably used to ______________.
A. dry air
B. cotton wool
C. ordinary water
D. air-free water

2. What are necessary steps to make sure the water in the tube is air free?

①Leave half a tube of water in it                ②Boil the water for some time
③Put some clean iron nails in the tube        ④Add some oil to the water
  A. ①②                  B. ①③                 C. ②③                D. ②④

3. We can conclude from the experiment that only ____________ makes iron rusty.

A. keep the air dry
B. keep the tube wet
C. make the nails rust
D. keep the tube clean

选择题

调查显示，北京、上海和广州三大城市年轻消费群体信用卡持有率超过六成，人均持有2.5 张。导致年轻人信用卡持有量大增的因素可能有

①信用卡消费安全性高 ②年轻人的收入大幅度增加

③信用卡方便购物消费 ④年轻消费群体的消费理念科学

A．①②

B．①③

C．③④

D．②④