问题 选择题

下图表示治理汽车尾气所涉及反应的微观过程。下列说法不正确的是

 

A.图中所示单质的化学式为N2

B.图中所示有三种氧化物的分子

C.反应后分子个数变少了

D.生成单质与化合物的质量比为7︰11

答案

  D

 

题目分析:由题的图标可知反应前为一氧化氮和一氧化碳,反应后生成氮气和二氧化碳,故A选项图中所示单质的化学式为N2是正确的叙述;B选项图中所示有三种氧化物的分子是正确的叙述;C选项图中所示有三种氧化物的分子是正确的叙述;D选项生成单质与化合物的质量比为7︰22,故答案选择D

阅读理解

阅读理解。

                                        Important tips for better flash (闪光灯、闪光) photos

     Don't stand too far back from your subject. The flash on most cameras will not cover any subject well over

three metres away. Even in non-flash photos many photographers stand too far away from their subjects. As a

result, the subjects are small with great areas of unimportant background.

     Watch the background carefully and be sure there are no mirrors or shiny things to reflect (反射) the flash

back to the camera lens (镜头).

     When taking pictures of people, ask them not to look into the lens but at a point over your shoulder, because

it is very possible that the flash will reflect from their eyes and there will be red eyes in the photo.

     Try to give the subjects an interesting background. If there is nothing for two metres behind the subject, the

background will come out black or very dark. Of course, you don't want an untidy background, because it will

take people's attention away from your subject.

     If taking a picture of a baby, be sure the room is as light as possible so that the flash does not hurt his / her

eyes.

1. To avoid red eyes in the photo, the best place people should look at is _____.

A. the sun in the sky

B. the mirror behind the photographer

C. the lens of the camera

D. a point over the photographer's shoulder

2. Which of the following is the right way to take a flash picture of a baby in a room?

A. Making the room as light as possible.

B. Having the baby sit in front of a mirror.

C. Helping the baby look at the camera lens.

D. Keeping the baby five metres away from the camera.

3. When taking flash pictures, we should be sure that _____.

A. there is nothing shiny in the background

B. there are interesting things in front of the subjects

C. there are as many beautiful things as possible in the background

D. there are great areas of black or dark background

单项选择题