阅读下面短文，从每小题所给的A、B、C、D四个选项中选出最佳选项。
Harry and Annie live a mile from the town, but they walk there to school every day. It is a pleasant walk around the pond* on their way to school. In winter, when the ice is thick and hard, they go across the pond. But their mother doesn't like them to do it unless* someone is with them.
"Don't go across the po nd today, children,"she says, as she kisses them goodbye one morning."It is beginning to thaw."
"All right, mother,"says Harry, not very happy, for he likes running and skating on the ice very much.
When they come to the pond, the ice looks hard and safe.
"There,"Harry says to his sister,"Let's skate over it."
"But you promise mother,"says Annie.
"No, I don't. I only say‘All right', and it is all right."
"I don't say anything, so I can do as I like,"says Annie.
So they step on the ice and start to go across the pond.
They don't go far before the ice melts*, and suddenly they fall into the water.
A man who is at work near the po nd hears the children asking for help and rushes into the water to save them. They are almost drowned * before the man can reach them.
They get home almost frozen* and learn a lesson they will remember for a lifetime.
¥200
¥100
You must know drug detection dogs*, they always help police a lot. But how about"drug detection squirrels"? Recently, Chongqi ng police have successfully trained* six squirrels to detect drugs. They began their work in early February.