| 阅读理解 |
| Take any long piece of paper. Now glue the ends of the paper together. You have made a ring. Take a second long piece of paper. Twist the paper once and glue the ends together. Now you have made a Mobius band. For people studying maths, this band is uncommon. This strange band was first made in the 1800s by a German man named August Mobius. Mr. Mobius studied maths. He wanted to find a way to show how this band works with maths. Understand it or not, this band has only one surface. You can find this out for yourself. If you draw a line on the surface of the paper before you twist and glue it, the line is only on one side of the paper. The paper has two surfaces. However, if you draw a line after you make the Mobius band, you can follow the line around all sides of the paper. In other words, the Mobius band must have only one surface. It is also very interesting to see what happens when you cut the band. If you cut the Mobius band in half once down the line you drew, you do not get two Mobius bands. Instead, after you cut the band, it turns into one large twisted ring. Then, if you cut this ring in half along the middle of the band again, you get two connected Mobius bands. Try it! |
| 1. What is a Mobius band? |
| A. A ling piece of paper. B. A paper ring for people to wear. C. A metal ring for music. D. An interesting twisted ring. |
| 2. How can you change the two surfaces of a long piece of paper into one surface? |
| A. Glue the ends of the long piece of paper. B. Cut the two surfaces of the paper into one. C. Draw a line in the middle of the paper. D. Twist the paper once and glue the two ends. |
| 3. What do you get if you cut the Mobius band along the middle? |
| A. A long piece of paper. B. Two long pieces of paper. C. Two Mobius Bands. D. One large twisted ring. |