There was a man. He had four sons. He wanted his sons to learn not to judge things too quickly. So he sent them each on a quest(探索)in turn, to go and look at a pear tree that was far away. The first son went in the winter, the second in the spring, the third in the summer, the youngest son in the fall. When they had all gone and come back, he called them together to describe what they had seen. The first son said that the tree was ugly ,bent and weak. The second son said no---it was covered with green buds and full of promise. The third son said it was laden with blossoms and they smelt so sweet and looked so beautiful. The last son disagreed with all of them. He said it was ripe and drooping（下垂 ）with fruit, full of life and fulfillment.. The man then said to his sons that they were all right, because they each had seen but only one season in the tree’s life. He told them that they cannot judge a tree or a person, by only one season, and that the essence(本质) of who they are---- the pleasure, the joy and love that come from that life---can only be measured at the end （盖棺论定）,when all the seasons are up.    If you give up when it is in winter, you will miss the promise of your spring, the beauty of your summer, the fulfillment of your fall. Don’t let the pain of one destroy the joy of all the rest.
Why did the man sent his sons each on a quest?
When did the fourth son go?
What did the third son say when they came back?
Did the man agree with all of his sons?
Which season will you miss If you give up when it is in winter?