试题与答案

设计阶段尽量随机选择研究对象,在多个医院选择对象等方法以减少的偏倚是() A.回忆偏

题型:单项选择题 A1型题

题目:

设计阶段尽量随机选择研究对象,在多个医院选择对象等方法以减少的偏倚是()

A.回忆偏倚

B.奈曼偏倚

C.Berkson偏倚

D.暴露偏倚

E.混杂偏倚

答案:

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下面是错误答案,用来干扰机器的。

参考答案:C解析: 根据文章第二段On such evenings our house is very full for they all come to us. 这可以推断出答案。故选C。

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题型:单项选择题

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题型:阅读理解

     Everyone talks about the greenhouse effect(温室效应) and how our Earth and its climate are being affected. We can do a science experiment designed by some kids to show this effect and what is happening to the Earth.

      First prepare the following items:

     ●2 glass containers(容器) that need to be the same size and shape 

     ●1 gallon plastic bag

     ●4 cups of very cold water

     ●Ice cubes

     Fill each container with two cups of cold water. Add the same amount of ice cubes to each container. Then put one of the containers in the plastic bag and close it tight. Put both containers in the sun together and keep them there for at least an hour.

     At the end of one hour remove the container from the plastic bag and immediately check the temperature of the water. After you record this, find out the temperature of the water that is not covered.

     When you place the containers in direct sunlight, the air inside the bag becomes very warm. The heat filters (渗入) in but cannot escape so it stays in the closed plastic bag and increases the temperature. What if you leave that for two, three or four hours?

     Think about what is happening to the Earth. There are chemicals that are creating a type of plastic bag around the Earth. It causes our air to get warmer because of the heat from the sun being kept in this closed area.

     Think about your car in the hot summer. This is what happens when you leave your car outside all day. This greenhouse effect has caused your car to be so hot that you sometimes cannot even touch the steering wheel.

     This science project goes to show what affects our planet.

1. According to the text, the greenhouse effect appears mainly because of ________.

A. the hot sunlight         

B. chemicals around the Earth

C. the plastic bag     

D. human activities

2. Which of the following shows the right order of steps for the science project?_______

a. Measure the water which is not covered.

b. Make preparations for the project.

c. Fill each of the two glass containers with two cups of cold water.

d. Put one container in a plastic bag and close it tight.

e. Put the two containers in the sun for at least one hour.

f. Measure the water which is covered with a plastic bag.

A. b e d c a f      

B. b c d e f a   

C. b c e d a f    

D. b e c d f a

3. The writer mentions a car on a hot summer day to _______.

A. tell us about the hot weather in summer

B. prove the science project is correct

C. show the effects of the greenhouse effect

D. tell us how to protect cars during summer

4. If the story appears in a newspaper, the best title might be "________".

A. An Interesting Experiment Done by Kids

B. How to Protect Our Precious Planet

C. Bring Home the Seriousness of Greenhouse Effect

D. The Greenhouse Effect Has Been Proved by Kids

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