阅读理解。
Winter is a time for many exciting sports: sledding (雪橇), skating and skiing. Skating and skiing needs
lots of skills (技巧). Sledding gives you good exercise and is lots of fun!
A sled looks like a boat. It can move easily over snow or ice. Early sleds were made of wood. Now
some better sleds are made of glass.
Sleds can be pulled by animals. In some very cold parts of the world, people make animals like dogs,
horses, and reindeer (驯鹿) pull goods or people in sleds.
People also sled for sports and fun. Driving a sled does not need much skill. The driver gives a kick
(踢) in the snow to start the sled. He or she can also ask someone else for help. In a sled, there can be one
person or several.
Usually, you have to lie on your back, feet first in a sled. As you travel, you move your body and feet
to keep it in the right direction (方向).
There is a special sled called the skeleton sled (骨架雪橇). It's very different.
On a skeleton, you lie on your stomach and drive the sled in a head-first way. It is very fast! Many
are afraid to ride it. But once they try it they want to do it again!
阅读短文，回答下列问题：
1. What are sleds made of?

2. What kind of animals can pull sleds?

3. What are sleds used for?

4. How do people sled? Describe the process.

5. What is a skeleton sled like?