It is sometimes said that strange flying objects have been seen high up in the sky. People call these strange objects Unidentified Flying Objects(UFOs). These UFOs caused a lot of interest. Some of the reports about them are difficult to believe. Some have been explained in scientific ways. Others have never been explained. Here is an account of UFOs from a report. Dennis Burdens, who wrote an article, tells us that he once saw a UFO himself. He was having dinner one night with a friend near Tripoli, Libya, and after dinner the two men walked across a yard to his room to look at some papers. Burdens noticed that the moon looked strange that night. "It wasn't the moon," was the reply. They watched the light and saw that it was moving. It seemed to be an object rather like a big plate. In some ways it looked like smoke with a light on it, but it wasn't smoke because it didn't change its shape. It was moving in a regular way. That is to say, it didn't go suddenly faster or more slowly, and it didn't go higher or lower. So the two men decided that there must be men in it. After that, Burdens said that he felt eyes looking at him. He was being watched in the darkness. When it was nearer, they noticed that the bottom parts were brighter than the top. The bottom was yellow and the top red. Then the object suddenly turned away and left Libya, moving very fast. On a later day Burdens talked to other people about it, and he found some who had seen it. They all described it in the same way. Could they all be mistaken? The UFO looked like  _  .
smoke a large plate light a jumping object