All living things on the earth need other living things to live. Nothing lives alone. Most animals must
live in a group, and even a plant grows close together with others of the same kind. Sometimes one
living thing kills another, one eats and the other is eaten. Each kind of life eats another kind of life in
order to live, and together they form a food chain (链条). Some food chains are simple, while others
are not. But all food chains begin with the sun, and all food chains become broken up if one of the links
disappears.
All life needs sunlight to live on. But only plants can use sunlight directly. Plants are "factories". They
make food from sunlight, water and things in the soil and air. Plants feed all other living things. Animals
can only use the sun's energy after it has been changed into food by plants. Some animals feed directly
on plants, others eat smaller animals. Meat-eating animals are only eating plants indirectly.
What about human beings? We are members of many food chains. We eat rice, vegetables, and fruits
and so on. We also eat meat and drink milk. But men often break up the food chains. They kill wild
animals. They also make rivers, lakes and seas polluted, when these rivers, lakes and seas are polluted,
the fish in them can not be eaten. If men eat the fish, they will get strange diseases.
Each form of life is linked to all others. Breaking the links puts all life in danger.
1. How does every living thing on the earth live?
A. Each plant can live alone.
B. Each animal can live alone.
C. If living things want to live, they must kill each other.
D. Every living thing on the earth can't live without others.
2. Which living things can use the sun's energy directly?
A. Animals.
B. Plants.
C. Animals and plants.
D. All living things.
3. Who often break up the food chains?
A. Human beings.
B. Animals.
C. Plants and animals.
D. Men and wild animals.
4. Which of the following do you think is the best title for this passage?
A. The sun's energy.
B. Plants.
C. Food Chains.
D. Living Things.
