三、阅读理解
A forest is like a football group. It sounds strange, but it's true. In a football game, each player does an important job, but they can't win on their own, so they work together. The same is true of all plants and animals in a forest. They depend on each other to live. We call this an ecosystem.

There are three jobs in an ecosystem: producer, consumer and decomposer. Giraffes can't produce food themselves, so they eat tree leaves. Then hungry lions or other animals eat giraffes. When these animals die, their bodies become part of the soil and help the trees grow. So the ecosystem can keep on going.
Ecosystems come in lots of kinds and sizes. A small back garden or a big sea can both be an ecosystem. The key is that an ecosystem has to be balanced. If there weren't animals to eat giraffes, giraffes would eat too many leaves, which is bad for the trees. Also, this would make it difficult for giraffes to find food in the long term. Different weather and natural disasters can change the ecosystems. People also bring problems to them by cutting down the trees and other activities.
Ecosystems are everywhere. They play an important part in our life. It is necessary for us to do what we can to keep them working well.
() 1. How many jobs are there in an ecosystem?
A. Five. B. Four. C. Three. D. Two.
() 2. What can we know from Paragraph 3?
A. People plant many trees in forests every year.
B. It's difficult for giraffes to find food nowadays.
C. Terrible earthquakes can change ecosystems.
D. Ecosystems only come in a back garden or a big sea.
() 3. What does the writer want to tell us in this passage?
A. To ask people to protect the ecosystems.
B. To introduce different jobs in the forests.
C. To teach us how to keep ecosystems balanced.
D. To show the writer's ideas of protecting animals.