练习材料：
When a light passenger plane flew off course some time ago, it crashed in the mountains and its pilot was killed. The only passengers, a young woman and her two baby daughters, were unhurt. It was the middle of winter. Snow lay thick on the ground. The woman knew that the nearest village was miles away. When it grew dark. she turned a suitcase into a bed and put the children inside it, covering them with all the clothes she could find. During the night, it got terribly cold. The woman kept as near as she could to the children and even tried to get into the case herself, but it was too small. Early next morning she heard planes passing overhead and wondered how she could send a signal. Then she had an idea. She stamped out the letters' SOS' in the snow. Fortunately, a pilot saw the signal and sent a message by radio to the nearest town. It was not long before a helicopter arrived on the scene to rescue the survivors of the plane crash.
任务配置：L0+L4
知识笔记：
course 航道
pilot 飞行员
stamp 踩
stamp out the letters 踩出字母
练习感悟：千万不要一心二用。自以为一件时间干了两件事，其实最费精力，而且效果不好。边看书边吃东西，边运动边看电视，都容易让自己变得浮躁。要干啥专心地干，不要干这个想那个。注意眼部的休息。看一会，休息五分钟。
