下图历史现象出现的主要原因是（    ）

B

    Sam was a fifteen­year­old boy living with his little sister, Julie. Their parents passed away long ago. Sam had to take care of Julie by himself.

One day, Sam woke up at three in the morning as usual. When Julie was sleeping alone, Sam left their little house to send newspapers. When he found an old man sitting in front of their house, Sam was so surprised that he stopped to look at him closely. It was an icy morning and he looked very cold.

    The poor old man didn't have anything to cover himself with. Sam went into his house to get the old man a blanket(毯子). However, there were no extra blankets, so Sam thought hard and took his father's coat. It was the only thing of his father's that he had left. Sam wrote a short note. "Sir, I found you sleeping in front of my house. This is my father's coat. I hope it fits you well." He put the note in a pocket of the coat and covered the old man with the coat. Then he went to work. When he came back, both the man and the coat were gone. Sam thought that it was the best thing he could do with his father's coat.

    That afternoon, Sam hurried home after school because Julie was at home alone. However, Julie and the old man were standing in front of the house, and Julie shouted to Sam, "Brother! He's our grandfather!"

    The grandfather smiled and said, "Sam, thank you for giving me the coat and letting me know how good my grandson is. This coat was the one that I gave my son a long time ago!"

阅读理解

    有两个孩子：一个喜欢弹琴，想当音乐家；一个爱好（hǎo  hào）绘画，想当美术家。

    然而不幸得很！想当音乐家的孩子，突然耳朵聋了；想当美术家的孩子，突然眼睛瞎了。两个孩子非常伤心，痛哭流涕（tì  dì），埋（mái  mán）怨命运对他们太不公平。

    恰巧，有位老人打他们身边经过，听见了他们的怨恨。老人走上前去，先对耳聋的孩子比划着说：“你的耳朵虽然坏了，但眼睛还是亮的，为什么不改学绘画呢？”接着，他对眼睛瞎的孩子说，“你的眼睛尽管坏了，但耳朵还是灵敏的，为什么不改学弹琴呢？”

    两个孩子听了，心里一亮。他们擦干眼泪，开始新的追求。

    说也奇怪，改学绘画的孩子渐渐地感到耳聋反而更好。因为他可以避免一切喧嚣的干扰，使精力高度专注。改学弹琴的孩子，慢慢地也觉得失明反倒（dào  dǎo）有利。因为他能够免除许多无谓的烦恼，使心思无比集中。

    果然，耳聋的孩子后来成了美术家，名扬四海；眼瞎的孩子后来成了音乐家，饮誉天下。

    一天，美术家和音乐家又遇见了那位老人，他俩非常激动，拉住老人连连道谢。

    老人笑着说：“不用谢，事实证明：只要努力，当命运堵塞了一条道路的时候，它，常常还留下另一道路的！”