15. What does the sign mean?

A. Recycle bottles and cans only.      

B. Recycle paper only.

C. Reduce bottles only.

D. Reduce paper only.

16. What does the sign mean?

A. You must cut down the trees.       

B. You can cut down the trees.

C. You mustn’t cut down the trees.   

D. You should cut down the trees.