解放军文职招聘考试智力

Take a second long piece of paper. Twist(扭转) the paper once and glue the ends together. Now you have made a Moby’s band(带子). For people studying maths, this band is uncommon.

This strange band was first made in the 1800s by a German named August Moby’s. Mr. Moby’s studied maths. He wanted to find a way to show how this band works with maths. Believe 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 Moby’s band, you can follow the line around all sides of the paper. In other words, the Moby’s band must have only one surface.

It is also very interesting to see what happens when you cut the band. If you cut the Moby’s band in half once down the line you drew, you do not get two Moby’s 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 Moby’s bands.

Try it!

1. What is a Moby’s band?

A. A long piece of paper. B. A paper rings for people to wear.

C. A metal ring for music. D. An interesting twisted ring.

2. Why did August Moby’s make this ring?

A. To help study a maths problem.

B. To show it’s the same as others.

C. To show the only surface of any band.

D. To find out how many sides it has.

3. 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.

4. What do you get if you cut the Moby’s band along the middle?

A. A long piece of paper. B. Two long pieces of paper.

C. Two Moby’s Bands. D. One large twisted ring.

5. Which of the following is NOT true? 

A. You can use any long piece of paper to make a Moby’s band.

B. Any long piece of paper has two surfaces.

C. The Moby’s band was first made about two hundred years ago.

D. You have to draw a line in the middle of the long piece of paper before making a Moby’s band. 

【答案与解析】这篇文章介绍了一种非常有趣、蕴涵着无穷奥妙的Mody’s带子。

1. D。第2段的第2句告诉我们：Twist the paper…，我们可以推断出它是An twist Ring, 即答案D(旋转的环)。

2. A。由第2段的第3句我们可以找到这道题的答案He wanted to find a way to show how this band works with maths，所以A是正确的。

3. D。可以将Two surfaces of along piece of page into one surface有 Mody’s band。而怎样做成Mody’s band 呢？第2段的第2句Twist the paper…告诉了我们选答案D。

4. D。根据第5段的第2句If you cut the Mody’s你可以得到一个很大的旋转环。The line you drew是画在整个Mody’s Band上面的，就得到D这个答案。而迷惑性较大的Two Mody’s Bands则需要cut this ring again。

5. D。由第4段的第1句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，我们得知a line是on the surface of the paper。也就是说在整个Mody’s Band上，而不是in the middle of the long piece of paper，所以答案选D。