（1）Trees are important to man in

way（s）.
A.only one
B.two
C.three
（2）What is the most important service of trees？
A.They give man shade and cool.
B.They help man to make money.
C.They help to prevent drought and floods.
（3）Which of the following is true？
A.Tree roots can break up soil.
B.Trees are not the best friends of mankind.
C.Tree roots are worthless.
（4）Which of the following is NOT true？
A.Tree roots carry away top soil.
B.Trees can make the rain sink into the ground.
C.Trees help bind the soil so that it won't be washed away easily.
（5）Why does land become desert after all trees are cut down？
A.There are too many rainfalls.
B.There are no longer trees to keep the rain and protect the soil.
C.Strong winds bring a lot of sand.