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 in order to live, and together they form a food chain(食物链)．Some food chains are simple, while others are not．But all food chains begin with the sun, and all food chains will be broken up if one of the living things disappears(消失)．
All life needs sunlight to live on．But only plants can use sunlight directly．Plants are “factories”．They make food from sunlight, water, air and things in the soil．
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 wheat, rice, vegetables, fruit 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 dirty．When these rivers, lades and seas are polluted, the fish in them can not be eaten．If men eat the fish, they will get strange diseases(疾病)．
Each form of life is linked to the others．Breaking the links will put all lives in danger．
(1)
How does every 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．
Both animals and plants．
D．
All living things
(3)
What do plants make food from? They make food from _________．
[ ]
A．
sunlight, water, air and things in the soil
B．
water, sunlight and things in the soil
C．
water, and things in the soil and air
D．
water, sunlight and things in the soil
(4)
Which of the following do you think is the best title for this passage．
Most American children eat potatoes．But many children don't know what of the potato is the best for food．Take a knife and cut from the middle of the potato a piece as thin as paper．Hold the piece between your eyes and light．You will see that the potato has skin(皮)，an outside rim(边缘) and an inside part．The outside rim which is right under the skin of the potato，is the most valuable part of all．But this is often thrown away with the skin．Even the skin itself is better for food than the inside．When eating a cooked potato，if you choose the inside and leave the outside，you are throwing the best part of it．If you can't eat the whole potato，eating the outside rim and leaving the inside will do．
(1)
How many parts does the potato have?
A．It has only one part，outside rim．
B．It has two parts，skin and outside rim．
C．It has three parts，skin，outside rim and an inside part．
D．It has four parts，middle，skin，outside rim and an inside part．
[ ]
(2)
What is the best part of a potato?
A．Outside rim． B．Inside part． C．Middle． D．Skin．
[ ]
(3)
What should you eat first if you can't eat the whole potato?
A．Skin only． B．Inside． C．Outside rim． D．Part of it．
