问题 问答题 简答题

什么叫燃点?

答案

参考答案:

燃点可燃液体表面上方的蒸汽和空气的混合物在某一温度下

与明火接触而发生燃烧,并能连续燃烧5分钟以上,能产生这种现象的最低温度称为

该液体的燃点,也叫着火点

,在燃点温度时,可以维持连续燃烧

阅读理解

It seems to be strange to you there is a blind spot(盲点)on the eyes,  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, Lon the left and R on the right. First, hold the card about 80 cm away and you 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' 11 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 does the letter disappear? It is because there is a blind spot on the eye. When the image(影像)of the letter falls on the blind spot,  it won't be seen.  That is why either of the letters disappears.

小题1:The writer of the passage thinks that_______ there is a blind spot on the eye.

A.few people know

B.no one knows

C.only you know

D.all the people know小题2:The word "disappear" in the passage means_______ in Chinese.

A.驱散

B.消散

C.消失

D.遗失小题3:You fail to see the letter L in the experiment because _______.

A.your eyes are poor

B.its image falls on the blind spot

C.your left eye is not open

D.you move it close to your eye小题4:In which order(顺序)should you do the experiment?

①Hold the card ②Move the card nearer ③Close your right eye

④write two English letters ⑤Look at the letter R ⑥Make a card

A.④⑥①②③⑤

B.①③⑥④⑤②

C.⑥①④③②⑤

D.⑥④①③⑤②小题5:The passage mainly tells us_______.

A.how to find the blind spot

B.an interesting experiment

C.where the blind spot is

D.there is a blind spot on the eyes.

单项选择题 A1型题