阅读理解
There are about fifteen hundred languages in the world. But only a few of them are very important. English is one of them. Many, many people use it, not only in England and the USA, but also in other parts of the world. About 200, 000, 000 people speak it as their own language. It is difficult to say how many people are learning it as a foreign language. Millions of people are trying to do so. Is it easy or difficult to learn English? Different people may have different answers. Have you ever noticed ads(广告) of this kind in the newspapers or magazines? "Learn English in six weeks, or give your money back. . . " "Easy and funny. . . " "Our records and tapes help you master English in a month."Of course, it never happened quite like that.
The only language that seems easy to learn is the mother tongue. We should remember that we all learned our own language well when we were children. If we could learn English in the same way, it would not seem so difficult. Think of what a small child does. He listens to what people say. He tries what he hears. So it is hard to say that learning English is easy. We must do a lot of practice. And practice needs great efforts(努力) and takes much time. Good teachers, records, tapes, books, and dictionaries will be helpful, but they cannot do the student's work for him.
表示图上1厘米的线段相当于实际距离( )千米，改写成数值比例尺是( )。