1 . What if we had the power to control time, instead of moving from the past to the present to the future? What if we could jump, loop and travel through time in a machine? What if we could go wherever and whenever we pleased?

This ability would allow us to witness historic wonders, change decisions and   see people from the past. We could right wrongs and stop wars from starting.

The mysterious puzzle of time has kept people debating its nature for hundreds of years. Science fiction writers have turned it into imaginative stories. Some scientists have even attempted to explain it using math. This math tries to make the dream of time travel come true.

The scientist Albert Einstein said that time and space are one thing. He called it “spacetime.” Einstein said that there are three dimensions in space: height, width and depth. A scientist named Hermann Minkowski added time as a fourth dimension.

Einstein introduced two ideas that have led to theories about the possibility of time travel. The first is relativity. The idea of relativity is that the force of gravity causes space to bend, which causes time to twist. The second idea focuses on special relativity. The idea is that a traveler moving super-fast through flat spacetime will enter the future. Einstein considered time “relative” because it is measured based on where we are on Earth or in space.

Stephen Hawking is a famous scientist. He believes that a time machine will never be built. If it were possible, he thinks we would already know. If a time   machine could be built, how come no one from the future has invaded us?

The first science fiction story with this theme is The Clock That Went Backward by Edward P. Mitchell, which was published in 1881. Since then, thousands of books, films and television shows have explored the idea of time travel, in which some tools such as phones, watches, photographs and old books take travelers backward and forward.

Will time travel ever happen? Who knows? Most important is to keep your eyes open and have a sense of wonder.

1. What is the author’s purpose of writing the first paragraph?

A．To show time and space are connected.

B．To show people’s interest in time travel.

C．To draw readers’ attention to time travel.

D．To make people believe time travel is possible.

2. Which of the following statement could Einstein agree with?

A．Time travel is possible in the future.

B．People can’t move faster than light.

C．Time travel is against scientific rules.

D．Spacetime is not a real thing in theory.

3. What is the last but one paragraph mainly about?

A．The first science fiction story.

B．Some tools used in time travel.

C．Edward P. Mitchell, the pioneer.

D．Different works about time travel.

4. What is the writer’s attitude toward time travel?

A．cautious.	B．pessimistic
C．sceptical	D．optimistic.