The sun is a huge, hot and bright star. It is important because without it there would be no life on the earth. The sun gives us light and heat.
All living things depend on the sun for their growth. Plants need light and heat to grow. They use the light from the sun to make food. But we human beings cannot make food by our own bodies from the sun. All the food we eat comes from plants in a food chain(链) . And the food chain starts with the sun . For example.
sun —→ potatoes  —→ chips
sun  —→ corn  —→ hens  —→ eggs
sun—→ wheat  —→ bread
Animals need sunlight, too. Just like us, their food comes from plants in food chain, which begins with the sun. For example,
Sun → leaf → caterpilllar(毛虫) → bird
Sun → seaweed(海藻) → small fish → whale(鲸)
With the help of sunlight, we can see things during the day. Even when the sky is cloudy, the sunlight is very strong and it shines through the clouds. If there was no sun, it would be dark all the time.
The sun is a           star.
A. huge, cold and bright        B. huge, hot and bright       C. small, warm and bright       
What are the two main things the sun gives us?
A. Light and heat.             B. Heat and eggs.           C. Corn and light.              
From the passage we learn that         .
A. when the sky is cloudy, there is no sunlight at all                 
B. without the sun there will be no life on the earth
C. we human beings can make food by our own bodies
All the food we eat comes from          in a food chain. And the food chain stars with the         .
A. plants; earth       B. plants; sun            C. animals; star      
Which is the best title (标题) for this passage?
A. Plants need heat and light to grow
B. All living things depend on the sun for their growth
C. The sun is very important