阅读理解。

1. Trees can get light from ______ in the daytime.

A. C0₂

B. O₂

C. the sun

D. the moon

2. Chlorophyll is in _______.

A. sunlight

B. soil

C. air

D. leaves

3. We can get more O₂ by _______.

A. planting more trees

B. cutting trees down

C. making the water in soil (土壤) polluted

D. making more CO₂

4. CO₂ from air and _______ can produce food for trees with the help of chlorophyll and sunlight.

A. water in the sea

B. water from soil

C. water in the river

D. O₂ into air

5. The picture tells us _______.

A. how trees let O₂ go into air in the sunlight

B. how trees let CO₂ go into air in the sunlight

C. the sunlight isn't important to trees at all

D. trees can take in O₂ and let out CO₂