下列各组划线字注音全部正确的是（    ）

规定：以方程x﹣y=0的解为坐标的所有点的全体叫做方程x﹣y=0的图象；

结论：一般的，任何一个二元一次方程的图象都是一条直线．

示例：如图1，我们在画方程x﹣y=0的图象时，可以取点A（﹣1，﹣1）和B（2，2），作出直线AB．

【解决问题】：

根据材料内容，选择正确答案。

    Jim, a young farmer, was once put into prison (监狱).

    One day, he got a letter from his mother. "I'm so worried about our farm," she wrote. "It's time to plant potatoes. I can't dig(挖) all the fields by myself. "

    Jim read the letter and became sad. "What can I do?" he thought. Then he had a good idea. He wrote to his mother, "Don't dig the fields. There's a pot of money in the earth. Don't plant potatoes until I come home."

    Some days later, Jim got another letter from his mother. It said, "Two days ago, about ten men came to our farm and dug all our fields. I can't understand it. It looks as if they were looking for something. What shall I do?"

    Jim smiled when he read his mother's letter. He wrote a letter to his mother at once. It was very short. Guess what it would say?