【解析】本题考查名词所有格。表示有生命的东西的名词及某些表示时间、距离、星球、世界、国家等无生命的东西的名词后加's来表示所属关系，叫做名词所有格。复数可数名词的所有格是在s后打小逗号，例如：3 hours' walk 三小时的路程；five minutes' walk 五分钟路程；two miles' distance 两英里的距离等。根据句意：从你家到学校有多远？步行约20分钟。故选C。
You Can Make a Windsock(风筒)
Have you ever seen a windsock blowing in the wind? Well, you can make one of your own! This is a fun project that you can do with things you may have. You just need to follow a few easy steps.
You will need:
● one piece of heavy colored paper ● five ribbons
● strong tape ● a string
● a pencil
What to do:
Step 1: Draw pictures on the paper. You can write your name on it. Do anything that will make it special to you.
Step 2: Make the paper into the shape of a tube. Hold one of the shorter edges(边缘) over the other. Then make them together with the tape at each end and in the middle.
Step 3: Use a pencil to make a hole into both sides of the tube. The holes should be only on one end of the tube. Pull the string through both holes. Then tie the ends of the string together.
Step 4: Now make five holes around the top of the other end of the tube. Put a ribbon through each of the holes. Tie a knot in the ends. Make sure the knots are bigger than the holes.
Now your windsock is ready to use, but how does it work? The shape of the tube plays an important part. Wind blows through the tube and makes it fly and dance around. Hold the windsock up in the air by its string and run around. It will fly behind you. You can also hang it outside and watch it dance around on its own!
51. You draw pictures on the paper to make the windsock _____.
A. fun B. heavy C. strong D. special
52. Which of these things do you need for Step 2?
A. Tape. B. Ribbons. C. A pencil. D. A string.
53. What do you do after you put ribbons through the holes in the tube?
A. Make holes in the tube.
B. Tape the tube together.
C. Tie knots in the ribbons.
D. Put a string through the hole.
54. What is probably the most important to make a windsock work?
A. Its shape.B. Its size.
C. The color of the paper.D. The number of the holes.
55. What is the main purpose of this article?
A. To tell an interesting story.
B. To explain how to do something.
C. To teach an important lesson.
D. To show what a windsock is like.