问题 选择题

下列语句中,不是命题的是(  )

A.直角都等于90°

B.面积相等的两个三角形全等

C.互补的两个角不相等

D.作线段AB

答案

A、正确,对直角的性质作出了判断;

B、正确,对面积相等的两个三角形的性质作出了判断;

C、正确,对互补的两个角的性质作出了判断;

D、错误,是叙述一件事,没作出任何判断.

故选D.

填空题
阅读理解

阅读理解

      Water is very important to living things. Without water there can be no life on the earth. All animals

and plants need water. Man also needs water. We need water to drink, to cook our food and to clean

ourselves. Water is needed in offices, factories and schools. Water is needed everywhere.

      There is water in seas, rivers and lakes. Water is found almost everywhere. Even in the desert part

of the world, there is some water in the air. You can not see or feel it when it is a part of the air. The

water in the seas, rivers and lakes is a liquid, the water in the air is a gas, and we call it water vapor (蒸气).

      Clouds are made of water. They may be made of very small drops of water. They may also be made

of snow crystals(结晶体). Snow crystals are very small crystals of ice. Ice is frozen water. It is a solid.

There can be snow and ice everywhere in winter.

     Water may be a solid or a liquid or a gas. When it is a solid, it may be as hard as a stone. When it is

a liquid, you can drink it. When it is a gas, you can not see or feel it.

1. Where can we find water?

A. We can find water when it turns into vapor.

B. Water can be found almost everywhere.

C. We can see water in deserts here and there.

D. Water is only in seas and rivers.

2. We can drink water when it is____.

A. a liquid  

B. a solid  

C. in the air  

D. turned into ice

3. Clouds are made of

A. seas, rivers and lakes      

B. blocks of ice

C. very small drops of water or snow crystals

D. solid, liquid and gas

4. Water has three states(状态). They are ____.

A. ice, snow and air    

B. solid, vapor, snow

C. drops of water, blocks of ice and crystals of water

D. solid, liquid and gas