汉武帝采取的利于抑制大商人牟取暴利的措施是（    ）

根据材料内容，选择正确答案。

    Mr. Brown is an old man. Every morning he goes for a walk in the park. And he comes home at twelve thirty for his lunch in the middle of the day.

But today a car stopped at his house at twelve 0'clock. Two policemen helped him get out. One of them said to Mr. Brown's daughter, "He can't find his way home in the park and ask us to take him home in the car."

    The daughter thanked the policemen and they leave. Then she asked her father, "Dad, you go to the park every day. But today you can't find the way. What's wrong?" The old man smiled like a child and said, "I can find my way home. But I don't want to walk home."

下列有关物质的区分方法不正确的是   (    )