小题1: ________In 1973, Jimmy Carter, ex-president of the Unit

小题1: ________
In 1973, Jimmy Carter, ex-president of the United States, saw a UFO—an Unidentified Flying Object. There were about 20 other people with him at the time, and they all watched the strange object for several minutes.
小题2: ________
Does this surprise you? It’s not unusual. About 15 million people all over the world think that they have seen a UFO, a recent report says.
小题3:_______
UFOs have become very popular. There are books and films about UFOs, we can watch imaginary flying saucers and visitors from space on television, and there are stories in the newspapers about strange objects. Some of the stories are very silly. Clearly, some of these “UFOs” were aircraft, birds, the moon, lights on the clouds, and so on. But some people believe that spaceships come from other planets, and some of the reports aren’t easy to explain.
小题4: ______
In 1947 an American businessman was flying his own plane during the day. Mr. Arnold was a sensible man and a pilot with many years’ experience. That day, he saw a row of strange flying objects. He could see them clearly, and he watched them for some time. Later he said that they moved “like saucers over water.” The name “flying saucer” was invented. The newspapers loved the story, of course, and they all wrote long reports about it.
小题5: ______
During World War II, pilots had reported strange round flying objects. Sometimes these objects flew beside their planes and followed them. At first, the pilots were afraid: they thought these objects were a new weapon. But the “weapon” didn’t harm them. The officers said the pilots were imaging things. The pilots got used to the strange objects.