The writer thinks that trees are useful to man in three ways, the most important of which is that ______.

A．She finished high school.
B．She had her 73rd birthday.
C．She got married and gave birth to nine children.
D．She began her studies at colleg
E．e. She went to the bank to borrow money.A. c,d, a,b, eB. a, e, c,d,bC. e, a, c, d, bD. a, c, e, b, d

A．Man has cut trees down in large quantities in order to make warships with which to gain an empire.
B．Man has cut trees down in large quantities only to find that with them gone times become harder for him.
C．Man has cut trees down in large quantities where the soil is hard and poor.
D．Man has cut trees down in large quantities because he has not come to know the importance of the first of the services trees do to him.