Professor Liang's question was a complete surprise to Long Yun, and he thought about it for a long time without getting an answer.

What kind of catastrophic event can completely extinguish a once glorious civilization, he has also imagined this question before, at that gathering of friends in the parallel world, in the face of Vladimir Putin, he asked about the parallel projection of this "quasi-father-in-law", and everyone present has thought about it for a while, but no one can say a convincing answer, whether it is "nuclear war", "plague" or the more nonsensical "comet hitting the earth", it seems that it cannot explain this problem.

Not only that, after meditating on the sofa for a while, the snooping of consciousness made Long Yun understand Liang Wuchang's thoughts, knowing that the question that the professor was considering was not "what kind of disaster can destroy a civilization", but "what kind of catastrophe will completely erase the traces of a civilization", this thought made him shudder slightly.

Yes, the destruction of civilization is already unimaginable, and what kind of catastrophe does it have to be to completely erase all the traces of a civilization?

Long Yun couldn't imagine it, he could only shake his head to Liang Wuchang blankly:

"Professor Liang, if you want to say 'wipe out the traces of civilization', it's not impossible, but you see, the earth is still in good shape, and there is more human civilization emergence and development, then I really can't say it, maybe ...... Does this prove that there is no so-called 'prehistoric civilization' on Earth? ”

"Hehe, yes, that's a very reasonable way of thinking."

Professor Liang responded with a hearty laugh to Long Yun's inference, and he put down the teacup in his hand and coughed lightly:

"About 'prehistoric civilizations'. That's not my main area of research. But since I brought it up. That's what I have in question.

Young man, your statement is very reasonable, if there was a 'prehistoric civilization' on the earth, and now there is not even a single 'Opaz', what does that mean? It shows that this civilization that once existed has 'completely disappeared' from the history of the earth out of thin air, not that it has perished, but that it has truly 'disappeared'. It's just an unbelievable thing, don't you say? Just look at dinosaurs, there are almost no intelligent species, let alone any civilization, but now there are dinosaur fossils and dinosaur nest fossils everywhere in the strata, which is not rare at all.

So I always felt that such a situation could not happen, otherwise it would be a little too strange: it was impossible for the civilization that had once appeared to disappear and find no trace on the earth, and it was absolutely impossible; Even if the earth is more than 4 billion years old, perhaps that 'prehistoric civilization' is very far away from today. It is impossible that there is no trace left until now.

How, what do you think of that? ”

"Well...... That's true. Mr. Liang, I also think this is unthinkable. ”

Originally, it was for the matter of "prehistoric civilization", but now his thoughts are focused on another argument, and Long Yun really can't imagine that a disaster of scale and intensity can completely erase the traces of civilization.

Roughly thinking about it, it is probably necessary to turn over the surface of the earth's crust, just like in the doomsday movie "2012", but the movie is just a movie after all, to say that the earth's crust will crackle and crack like tree bark, and then tumble and melt into magma, if such a disaster occurs on the earth, all living things are afraid that they will be extinct, so what is the "human" behind it, and where is the "human civilization" behind it?

I can't imagine that it is "impossible" for people's thinking, it is a very natural way of thinking, and it is not unreasonable for Long Yun to think so.

So he chatted with Professor Liang for a while, ended the whimsical discussion about "prehistoric civilization", and turned to the "step theory" of scientific and technological development; After reading Liang Wuchang's popular science book before, Long Yun put forward some examples in the book for discussion and analysis, which happened to be a better understanding of the research ideas of this scientist.

During the conversation, he was quite surprised to find that the development of human science and technology is really quite in line with the "step theory", which sounds incredible, but it is a fact hidden in the depths of the vast literature, but no one has paid attention to it before, or the information collected is not comprehensive and detailed, so no conclusion has been reached.

For such a conclusion, Long Yun himself is not a professional, and he can only express his surprise, he also went to the restaurant with Professor Liang Wuchang to eat at noon, of course, he called Ling together.

On the campus of Peking University near the end of the year, there are still a lot of students, seeing the eye-catching president school flower appear in the restaurant, many people actually have the meaning of coming forward to talk, but Liang Wuchang and Professor Liang are also celebrities in the school.

Malicious speculation may not be enough, but some fantasies such as "unspoken rules" may be inevitable, which makes Long Yun, who is sitting at the table, unhappy.

However, this is unpleasant, and he is the only one, and as a full-time guard, he is almost accustomed to it.

Originally, in the face of the Peking University school flower who has a unique appearance and temperament, it is not surprising that any man has some kind of fantasy, if he really cares about it, then does he have to do anything else as a guard?

After the visit to Peking University, Long Yun drove home with Shangguan Ling as usual in the evening of the same day.

After entering the door, seeing that Su Xue, who had hitchhiked back earlier, was preparing dinner, Long Yun, after changing clothes and washing, naturally went into the kitchen to help, and asked the eldest lady to go upstairs to continue to work on the unfinished project work during the day; When he came to the kitchen and took the vegetable pot from his lover's hand, he smiled at the busy little girl, knowing that she also enjoyed this kind of leisurely time when the two of them cooked together, especially without fiddling with the cumbersome vegetable cutter, and now his mood has become extraordinarily good.

"Long Yun, is the discussion with Teacher Liang still enjoyable today?"

"Well, it's okay; ――It's very good, although there are still some questions that I haven't figured out, but I have gained a lot. ”

Relying on the connection of consciousness between the two, the conversation between Long Yun and Su Xue, others may sound confused, but the communication between the two is very pleasant, he slightly reviewed the long conversation during the day, and came to such a conclusion, although he himself is a little unsure, whether that casual conversation has solved his inner doubts.

Su Xue, who was busy making vegetable salad next to Long Yun, tied a neat apron around her waist and tied her long hair back behind her head, had been working in a good way, and now she noticed her lover's thoughts, she raised her hand and gently touched Long Yun's arm, asking him not to be stunned, and she took a large bowl and put the cleaned strawberries into it one by one, while the corners of her mouth were upturned, and she asked her boyfriend with a little resentment:

"Then, have you opened the gift that people gave you yesterday?"

"- Gifts, gifts?"

didn't ask, and suddenly remembered yesterday's incident, Long Yun remembered that he received a gift from his lover yesterday, and he couldn't take too many things at that time, so he temporarily asked Su Xue to mention it at home; As a result, I patronized and talked to the two girls after a long time at night, and was later distracted by the "Noh Medium", and then I completely fell into the erotic desire for the pianist, and I even forgot about it!

"That's—uh......"

"Hehe, look at you like this, no one said they wanted to blame you."

Suddenly, she caught the thinking activities of her lover, and suddenly noticed the abrupt and bizarre word "energy medium", Su Xue, who had already known this kind of storage from Long Yun's mouth, was not too surprised, she knew that her lover would find time to discuss this qiē with herself, so she smiled at him quite charmingly:

"So, take it apart and take a look at it later when you eat, okay?"

"Good, good! Hey hey ......"

After receiving the lover's order, when the three of them were sitting in the living room to eat together that night, Long Yun took the beautifully packaged gift box from Su Xue and opened it.

In fact, he doesn't need to open the package, and he can know what is inside, but after a few months of getting along, his emotional intelligence is now much higher than when he first saw Su Xue, at this time, of course, he will not use any superpowers stupidly, but quite solemnly open the package, only to see a light-colored carton inside, after opening it, he saw two gifts lying on the sponge lining the carton.

"Wow, this is- I'll take a look, is it a watch and a fruit knife?"

"- W-what?"

Seeing Long Yun sitting on the sofa and opening the gift box, the eldest lady next to her with a calm expression but her eyes fell on the man's face, as soon as she heard this, she couldn't help but ask, which shocked Long Yun, who was joking, he didn't expect this eldest lady's reaction to be so intense, and when he tilted his head to look over, he heard Su Xue next to him sneer:

"Okay, don't be kidding, we don't believe you can't recognize it~

How's that, like? ”

"Oh-hehe, I'm making a bad joke, a bad joke,"

I was going to joke with the two girls, but the eldest lady next to him reacted violently, although Long Yun was very surprised, he still quickly clarified, he respectfully took out a "watch" and a "fruit knife" in the carton, and carefully looked at it in his hand for a while, knowing that his first impression was correct, this was really not an ordinary watch and knife, but a flight watch and flying knife used by pilots.

"Flight watch" and "flying knife", it seems to be a magical equipment that can fly, but of course it is not, to put it bluntly, there is no essential difference between it and ordinary watches and swords, but it is still very important as a necessary item for pilots.

Let's talk about the "flight watch" first, although there are several systems in modern aircraft to indicate the time for the pilot, but a piece of equipment that is not disturbed by the outside world and provides time indication for the pilot is still essential; As for the "flying knife", it may not be useful in normal flight, but it can come in handy in case of an emergency. (To be continued......)