A、Their works were unsigned. B、Many of their works were destroyed. C、They never stayed in one place for a long time. D、They work

So, now we are in the room with naive art, produced in the United States during 18th and 19th centuries. At that time, people of many nations had come together to form a single nation. The future of these people was unknown and they didn’t share a history together. The absence of tradition created a need for inventing a new one. These were some of the factors allowed naive art to grow as an art form in the United States. Because everything was new and without past, there was no such thing as art education. That’s how these artists got to be called naive artists. Most of you probably already know the French word naive meaning not have much knowledge. So, unlike professional artists, naive artists didn’t have formal training in different academy and studios. Instead, since they were eliminated by tradition, they made their own rules, were generally self-taught and their paintings had a true feeling for color form and world around them. There’s very little known about early naive artists in the United States because many of them did not sign their works. However, we do know that they followed similar themes. Many naive artists started out as portrait painters. They travel from town to town and made portraits for different families, especially in the days before photography. People generally wanted portraits as evidence of their existence for future generations. Compared to French naive paintings that are less realistic, naive artists in United States painted images that were neat, positive, extremely accurate and almost photographic. Now, in the next room, let’s take a look at naive artists’ work in France.
Now listen to the following recording and answer questions 19 to 21.
19. How did naive artists differ from professional artists?
20. How did the speaker describe the paintings of the American naive artists?
21. According to the speaker, what factor makes learning about early naive artists difficult?