The Bermuda Triangle The Bermuda Triangle is a place in the North Atlantic Ocean where lots of ships and planes,such as a group of planes called Flight 19 in 1945 and a big ship called the USS Cyclops in 1918,have gone missing.People have come up with many ideas about why this happens,like strange magnetic fields,or even aliens,but no one knows for sure.

Atlantis Atlantis is a place that many people believe existed a long time ago but has now disappeared under the ocean.The idea of Atlantis first came from a story told by a Greek thinker called Plato.He said Atlantis was a big island with a rich and powerful civilization（文明）,but it sank into the sea after a big war.People are interested in the lost civilizations and whether developed ancient people really existed.Many explorers have tried to find Atlantis,but no one has been able to prove it really existed.

The Wow!Signal In 1977,scientists at Ohio State University were listening to signals from space with a big radio telescope.Suddenly,they heard something very strange:a strong,short signal that looked like it might be a message from another planet.The researchers were so surprised that one of them wrote"Wow!"in the notes.It\’s one of the few signals that scientists have ever detected that could possibly be a message from another civilization on another planet.Many scientists have tried to listen for the signal again,but they haven\’t been able to hear it since.

（1）Which may explain the disappearance in the Bermuda Triangle? ______
A.Plane or ship accidents.
B.Strange magnetic fields.
C.A natural disaster.
（2）Who first mentioned the idea of Atlantis? ______
A.A modern-day explorer.
B.A Greek thinker called Plato.
C.A scientist studying ancient civilizations.
（3）What does the underlined word "existed" mean? ______
A.was present in the world as a real thing
B.was lost and impossible to find
C.fell to a lower place
（4）What made scientists think that there might be aliens? ______
A.A message from another planet.
B.A strong,short radio signal from space.
C.A new planet.
（5）What is the main topic of the three texts? ______
A.Unsolved mysteries.
B.Famous explorers\’ discoveries.
C.The history of ancient civilizations.