下列说法正确的是[ ] A、Na2O2 晶体中阴离子和阳离子的数目之比为1:1

题型:选择题

问题:

下列说法正确的是[ ]

A、Na2O2 晶体中阴离子和阳离子的数目之比为1:1

B、只有非金属元素之间才能形成共价键

C、分子晶体中一定含有共价键

D、在晶体中只要有阴离子就一定有阳离子

考点:离子化合物共价键
题型:选择题

     The over 55s who grew up watching blackandwhite programs and films are more likely to dream in

grey, research suggests.

     And the under 25s who have watched color TV all their lives tend to have colorful adventures in_the_

land_of_nod.

     Research from the first half of the 20th century, especially in the 1930s and 1950s, suggested that most dreams are in black and white.

     But results from tests in the 1960s and later suggested that up to 80 per cent of dreams contain some

colors.

     Since this period marked the transition  (过渡) from blackandwhite films and TV to widespread

Technicolor (彩色印片法), an obvious explanation was that television was influencing dreams, but

differences  between  the  studies  prevented  the researchers from drawing any firm conclusions.

     Later studies asked subjects  (实验对象)  to complete dream diaries immediately they woke up, but 

 the  earlier  research  used  questionnaires completed in the middle of the day, so the subjects might have

simply forgotten color elements in their dreams and assumed they were grey.

     To solve the problem, psychologist Eva Murzyn asked 60 subjects, half of whom were under 25 and

half over 55, to answer a questionnaire on the color of their dreams and their childhood exposure (暴露)

to films and TV.

     The subjects then recorded different aspects of their dreams in a diary every morning.

     She found there was no significant difference between results drawn from the questionnaires and the

dream diaries.

     She then analyzed data to find out whether an early exposure to blackandwhite TV or films could still

have a lasting effect on her subjects'dreams,40 years later.

Less than five per cent of the under25s'dreams were black and white.But the over55s who had access to

blackandwhite media in their younger days reported dreaming in black and white roughly a quarter of the

time.

     Murzyn said, "There could be a critical period in our childhood when watching films has a big influence on the way dreams are formed." People's attention might be heightened during the time they are watching

TV or films.

1. "this period" in  the fifth paragraph refers to________.

A. the 20th century  

B. the 1930s

C. the 1950s  

D. the 1960s and later

2 The underlined words "in the land of nod" in Paragraph 2 means________.

A. in the evening  

B. during travelling

C. in a dream world  

D. when they are thinking

3. Murzyn's study was different from other studies because  ________.

A. more people of different ages were involved

B. both diaries and questionnaires were used

C. more advanced technology was used

D. subjects were given more time to record their dreams

4. From the passage, we can learn that________.

A. studies on the color of dreams have been going on for many years

B. the results of the previous studies on dreams couldn't be trusted

C. older people are more likely to be influenced by TV viewing

D. the colors of TV sets are more likely to appear in viewers'dreams

5. What is the main idea of the passage?

A. The color of people's dreams changes along with their ages.

B. TV  viewing has  different  influences  on different people.

C. Childhood TV viewing may determine the color of dreams.

D. Childhood TV  viewing  may  influence  a person's later life.

题型:选择题

()指的是公共服务实现公共管理目标的程度,如福利状况的改变程度、公 * * 品使用者满意程度等。

A.效果

B.效率

C.宗旨

D.定位

题型:选择题

关于传染的概念,哪项是不正确的()

A.传染又称感染

B.是病原体对人体的一种寄生过程

C.传染包括机会性感染

D.传染亦包括所有寄生物对人体的共生状态

E.传染后可产生5种不同的感染谱,传染病仅是表现之一

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教育者向受教育的医务人员传授医学道德规范的医学道德教育方法是()

A.言教

B.奖惩

C.身教

D.榜样

E.引领学生进行实践

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1927年前后,电影中先后掀起了古装、武侠、神怪等一系列热潮,使这种末流的商业性市民电影彻底统治了中国影坛。在这些影片中,赚钱是唯一的目的,艺术上放弃了严肃的追求。正是这些末流的市民电影与郑正秋等较严肃的创作一起,为中国电影中“()”传统的形成奠定了最初的基础。

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