1 . Complete the passage using the correct forms of the words in the box. Do you believe Hawking’s predictions?

pros and cons             take over            on a scientific basis            have an urge to          superior conflict with          backwards

Time travel, alien invasions, and artificial intelligence have always been popular themes in science fiction. However, these were never the exclusive domains of sci-fi writers. Some scientists also    1     explore these themes    2    . Take time travel as an example. Many fascinating stories based on time travel go either    3     or forwards in time. However, the former is not really an option. World-famous scientist Stephen Hawking once explained that travelling into the past would     4    the basic rule that cause comes before effect. But it would be possible to travel into the future in a vastly     5    spaceship approaching the speed of light. In addition to the question of time travel, Hawking also expressed his opinions on alien invasions and Al development. When many scientists and scholars were still arguing about the     6    of alien existence and AI development, Hawking said he believed aliens would invade Earth, and that humans would eventually    7     by Aland robots.