"Listen carefully to what I say," the time traveler said, "I shall tell you something that you will not agree."
"Why will we not agree?" I asked.
"Because the science and mathematics you know are not correct," he said. "You believe there are only three dimensions(三维空间)-length, breadth(宽) and thickness."
"There is nothing to argue with that, " the youngest member of our little group said.
"Exactly!" the time traveler answered, "But there is also a fourth dimension - time."
"We all know about time, " another member of the group said. "Time passed."
"I do not agree," the time traveler said, "Length, breadth and thickness do not pass. They stay in the same place in space. We move about them. I can prove that time is the same. It does not pass. We move in time the same way that we move in breadth, length and thickness."
None of us believed the time traveler, and we argued with him for many hours.
"If we could travel back in time," the scientist said, "We could do things to change the future."
"If we could travel forward in time," the doctor(博士) said, "we could do things that change our present."
The time traveler smiled, "It is clear," he said, "that there is only one way I can show you that I am right. We must do an experiment. Please wait here."
He left the room and soon returned, carrying what looked like a clock.
"This is a model of a time machine. It took me two years to make it," the time traveler said. "I want all of you to understand that when I start the machine, it will immediately travel in time and disappear from the present."
He turned to the youngest of all. "Give me your hand," he said.
The young man put out his hand. The time traveler took it and placed it on the machine. Immediately, there was a sudden wind, and the little machine disappeared.
I was certain this was not a trick, but the doctor was not so sure.
"Are you asking us to believe," he said, "that the machine is now in a different time?"
"Certainly! In my laboratory, a full-size machine is almost complete. As soon as it is complete, I shall send myself on a journey through time. Would you like to see my machine?"
"Are you serious about this?" the doctor asked.
"I have never been more serious about anything," the time traveler said, "Come."
We followed him to his laboratory. There, we saw the actual machine, not quite complete, but large enough for a man to sit in.
