When I was young, I had an old neighbor named Dr. Gibbs. He didn’t look like any doctor I’d ever known. He never shouted at us for playing in his yard. I remembered him as a neighbor who was nicer than anyone else in the neighborhood.
When Dr. Gibbs was happy, he was planting trees. And his life’s goal was to make it a forest.
Dr. Gibbs had some interesting theories about planting. He talked about trees that weren’t watered would grow deep roots in search of water. So he never watered his trees. He planted an oak (橡树) and, instead of watering it every morning, he beat it with the rolled-up newspaper. I asked him why he did that, and he said it was to get the tree’s attention.
Dr. Gibbs died a couple of years. Every now and again, I walk by his house and look at the trees that he planted twenty-five years ago. They’re very strong now.
I planted a couple of trees a few years later. I watered them regularly and took good care of them. Whenever a cold wind blows, they shake their leaves and branches.
The funny thing about those trees of Dr. Gibbs was that difficulty seemed to help them in ways comfort and ease never could.
What was Dr. Gibbs’ life goal?

A．To build a forest.	B．To save more lives.
C．To make a lot of money.	D．To study plants.

One of Dr. Gibbs’ theories about planting was that ______.

A．he often talked to the trees	B．he kicked the trees heavily
C．he never watered the trees	D．he buried the leaves around the roots

What does the writer mainly want to tell us?

A．Trees are not as weak as we think.

B．We should listen to others’ advice.

C．Difficulty is necessary for growth.

D．Planting trees is good for the environment.