题目内容：

It seems to be strange that there is a blind spot in the eye. Here is an interesting experiment (实验) that can make something disappear when one eye is open.

Make a card about the size of a postcard and write two English letters "L" and "R" on it. "L" is on the left and "R" on the right. First, hold the card about 80 cm away and you can see both the letters. Then close your right eye and look at the letter "R" only with your left eye. And now, as you move the card slowly towards you, you'll find the letter "L" disappearing. But if you move the card nearer to your face, the letter will be seen again. Now do the same experiment with your left eye closed; you'll find the letter "R" disappearing.

Why do the letters disappear? It is because there is a blind spot in the eye. When the image (影像) of the letter falls on the blind spot, it won’t be seen. That’s why one of the letters disappears.

1.The writer of the passage thinks that _______ there is a blind spot in the eye.

A. few people know

B. no one knows

C. most people know

D. all the people know

2.The word "disappear" in the first paragraph means _______ .

A.消亡              B.丢失

C.消失              D.丧失

3.You fail to see the letter "L" in the experiment because _______ .

A. your eyes are poor

B. you move it close to your eye

C. its image falls on the blind spot

D. your left eye is not open

4.In which order should the experiment be done?

a. Hold the card.

b. Move the cards nearer

c. Close your right eye.

d. Write two English letters on the cards.

e. Look at the letter "R".

f. Make cards.

A. d. f. a. b. c. e.

B. a. c. f. d. e. b.

C. f. a. d. c. b. e.

D. f. d. a. c. e. b.

5.This passage mainly(主要)tells us _______ .

A. there is a blind spot in the eye

B. an interesting experiment

 

C. where the blind spot is

D. how to find the blind spot