Below is a description of a single scientific experiment. It shows us how iron reacts (反应) with air and with water. Aim: To find out if iron rusts(生锈) (a) in dry air; (b) in water that has no air in it (air-free water) ; (c) in ordinary water. Materials: Some clean iron nails (铁钉) ; test tubes(试管); test tube holder; cotton wool; oil; Bunsen burner. | |
Iron in dry air Method (1) Put some iron nails at the bottom of a test tube. (2) Push some cotton wool down the tube. (3) Leave the tube for one week. Result After one week, the nails have not rusted. Conclusion Iron does not rust in dry air. | (4) Add some oil to the water. (This will keep air out of the water.) (5) Leave the tube for one week. Result The nails do not rust in the tube with air-free water. Conculsion Iron does not rust in air-free water. |
Iron in ordinary water Method (1) Half –fill a test tube with water and add two or three clean nails. (2) Leave the tube for one week. Result The nails rust in the tube with ordinary water. Conclusion Iron rusts in ordinary water. (238 words) | |
Iron in air-free water Method (1) Half-fill a test tube with water. (2) Boil the water for three minutes. (This makes sure there is no air in the water.) (3) Put two or three clean nails in the water. | |
1.In the first part of the experiment the cotton wool is most probably used to ____.
A. keep the air dry B. keep the tube wet
C. make the nails rust D. keep the tube clean
2.What are necessary steps to make sure the water in the tube is air-free?
① Leave half a tube of water in it.
② Boil the water for some time.
③ Put some clean iron nails in the tube.
④ Add some oil to the water.
A. ①② B. ①③ C. ②③ D. ②④
3.We can conclude from the experiment that only ____ makes iron rusty.
A. dry air B. cotton wool
C. ordinary water D. air-free water
It seems to be strange to you there is a blind spot on the eyes. Here is an interesting experiment 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 on 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’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 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.
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. most people know D. all the people know
2.“a blind spot” in the passage means ________ in Chinese.
A.污点 B. 消散 C. 盲点 D. 遗失
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
4.The passage mainly (主要) tells us _______.
A. how to find the blind spot
B. an interesting experiment
C. where the blind spot is
D. there is blind spot on the eye
完形填空
I lost my sight when I was four years old by falling off a car and landing on my head. Now I am thirty-two. I can’t remember the brightness of sunshine and what color red is clearly. It would be ________ to see again, but a disaster can do strange things to people. I don’t mean I would ________ to go without my eyes. I simply mean that the loss of them made me appreciate(珍惜)more what I had ________ .
My parents and my teachers saw something in me---a potential(潜能)to live---which I didn’t see, and they made me want to fight in out with blindness.
The ________ lesson I had to learn was to believe in myself. I am not talking about simply the kind of self-confidence that helps me down so unfamiliar staircase alone. I ________ something bigger than that: a confidence that I am, although being imperfect, a real, positive(积极的)person; that there is a special place where I can make myself fit.
It took me years to discover and strengthen this confidence. It had to start with the easy and simple things, ________ a man gave me an indoor baseball. I thought he was laughing at me and I was ________ . “I can’t use this,” I said. “Take with you,” he encouraged me, “and roll it around.” The words were always in my head. “Roll it around!” By rolling the ball I could hear where it went. This gave me an idea how to achieve a goal I had thought ________ before; playing baseball. At Philadelphia’s Overbrook School for the Blind I ________ a successful skill of baseball. We called it ground ball.
I have set ahead of me a series of goals and then tried to reach them, one at a time. I had to be clear about my limitations(限制). It was no good crying for something that I knew at the start was wildly out of reach because that only invited bitterness of failure. I would fail something anyway, ________ on the average(平均)I made progress.
1.A. helpful B. wonderful C. hopeful D. successful
2.A. fail B. try C. want D. prefer
3.A. lost B. left C. used D. cared
4.A. hardest B. boring C. simplest D. easiest
5.A. think B. consider C. guess D. mean
6.A. Later B. Soon C. Once D. Then
7.A. worried B. hurt C. shocked D. encouraged
8.A. important B. unimportant C. possible D. impossible
9.A. invented B. discovered C. ordered D. directed
10.A. so B. for C. but D. and
--- Do you mind me closing the window? It’s a bit cold.
--- ________. Do it, please.
A. Not at all B. Of course
C. You’re welcome D. Don’t ask me
—Could you tell me __________?
—Certainly. In half an hour.
A. how long will the train to Beijing leave
B. when the train to Beijing would leave
C. How soon the train to Beijing left
D. How soon the train to Beijing will leave
----Do you want to _____ at the meeting? ---No, I have nothing to _____.
A. say, speak B. tell, talk
C. say, say D. speak, say
