(
A.The sun changes their colour.
B.Tiny algae(海藻) give colour.
C.Fish paint them.
B
) 6. Why are coral reefs colourful?A.The sun changes their colour.
B.Tiny algae(海藻) give colour.
C.Fish paint them.
答案：B
(
A.There is much ice.
B.They can’t find enough food.
C.They find no space to live in.
C
) 7. Why are polar bears in danger?A.There is much ice.
B.They can’t find enough food.
C.They find no space to live in.
答案：C
(
A.Grass and flowers.
B.Fruit and vegetables.
C.Fish and insects.
C
) 8. What do birds find in wetlands?A.Grass and flowers.
B.Fruit and vegetables.
C.Fish and insects.
答案：C
(
A.Make oxygen.
B.Break down dead leaves.
C.Grow fruit.
B
) 9. What do mushrooms do in forests?A.Make oxygen.
B.Break down dead leaves.
C.Grow fruit.
答案：B
(
A.To look pretty.
B.To stay safe.
C.To stay warm.
B
)10. Why do mountain hares turn white?A.To look pretty.
B.To stay safe.
C.To stay warm.
答案：B
( )11. What’s the date today?
A. March 20th.
B. March 21st.
C. March 22nd.
( )12. What is the main topic of the poster?
A. How to search for information.
B. How to save water.
C. How to use water.
A. March 20th.
B. March 21st.
C. March 22nd.
( )12. What is the main topic of the poster?
A. How to search for information.
B. How to save water.
C. How to use water.
B
B
答案：B B
( )13.
( )14.
( )15.
A
( )14.
C
( )15.
C
答案：13.A 14.C 15.C