在市场细分过程中，所细分出来的市场应当比较清晰，可以大致判断其市场容量，这属于市场细

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?  

酸吗啡溶液，遇甲醛硫酸试液呈（）.

A.绿色

B.蓝紫色

C.棕色

D.红色

E.不显色

对于房屋建筑及构筑物的岩土工程勘察，在初期阶段勘察工作量的布置应符合一定原则，下列各原则中错误的是（）。

A．勘察线应垂直于地貌单元、地质构造、地质界线位置

B．在建筑物的轮廓线上及中心点应布置勘探点

C．地形平坦地区，可按网格布置勘探点

D．每个地貌单元均应布置勘探点

核桃壳反冲洗水进入反冲洗缓冲罐，这些水转入（）入口重新进行处理。

A、三相分离器

B、斜板除油器

C、溶气浮选器

D、核桃壳

吸附塔充液排气结束后，将塔压控制在（）。

（A）0.35Mpa

（B）0.60Mpa

（C）0.88Mpa

（D）0.15Mpa