阅读理解。
     Plants are very important living things. Life could not go on if there were no plants. This is because
  plants can make food from air, water and sunlight.  Animals and men can't  make food from air, water
 and sunlight. Animals get their food by eating plants and other animals.  Therefore, animals and men
 need  plants in order to live.  This is the reason why we find so many plants around us.
      If you look carefully at the plants around you, you will find that there are many kinds of plants. Some
 plants are large while others are small. Most plants are green.
      Some plants have many small leaves.  Others have only a few.  There are many kinds of leaves.
 Leaves are of different shapes and colors.
      Leaves are also different in other ways.  Some leaves have long thin parts at the end, we call them
 leaf stalks, some have short leaf stalks, others even have no leaf stalks.  The leaf edges (边缘)  are also
 different. Some leaves have smooth (平滑) edges. Some have wave-shaped edges. Others have edges
 like the teeth of a saw (据子).
1. Which of the following shows the right relation (关系) according to the first paragraph?
    
2. Plants are important because _____.
    A. we need to eat plants every day
    B. men can't live without plants 
    C. we can see so many plants around us
    D. animals eat plants as their only food
3. We know from the passage that _____.
    A. all leaves have leaf stalks
    B. all leaves have smooth edges
    C. plants are different in shapes but have the same color
    D. leaves are different in shapes and colors
4. The underlined words "leaf stalks" in the last paragraph mean _____.
    A. 叶边        
    B. 叶纹        
    C. 叶柄    
    D. 叶尖
5. The main idea of the passage  is  _____.           
    A. how plants help men and animals
    B. plants are important and they are quite different
    C. plants are more important than air, water and sunlight
    D. why we find so many plants around us