Of course, it is possible. Of course there is.

Of course, it could also be that there isn't.

When Lin Chaoxi opened her eyes, her first reaction was that the space around her was very large, completely different from the environment in Old Lin's office. She had obviously come to a parallel space again, which was good.

But then, the corners of her lips hurt, and she heard a very sharp female voice nearby. Her eardrums felt stinging.

There was a smell of disinfectant in her nostrils, and a purple color came into view. It took Lin Chaoxi a while to realize that it was the color of her skin. There were large abrasions on it, and after being disinfected with disinfectant, such a rich color was left behind.

She looked at her wound for a while, then gently touched the corner of her mouth with her hand. The stinging sensation made her senses more real.

She really came back.

But what happened?

"Look at what you look like now! Do you still look like a student? Are you fighting like a gangster?!"

The seams pierced through the skin, and an angry voice from above explained the situation directly.

There was a slight "swish" sound.

Lin Chaoxi realized that she had returned to the first year of high school, when Old Lin had not yet had a car accident and everything was still possible.

Now, she had just finished a fight with someone and both of them were injured. She is now receiving treatment in the high school infirmary.

The person who had just been talking about her was Ms. Mei, the head teacher of the Grade 1 class. As if responding to Ms. Mei's reprimand, the doctor applied force on his hands.

Lin Chaoxi noticed that in addition to the wound that had just been disinfected with purple medicine, there was another wound on her body that was being sutured.

It was a knife wound, very obvious.

However, she did not immediately recall the specific reason why Gao Lin and Xi had fought, although for her, there were more important things now.

The school doctor finally tied the wound sutures. The head teacher was still nagging her. Lin Zhaoxi looked at the clock on the wall. It was 5:40 in the afternoon. She was wearing a school uniform and carrying a schoolbag. She must have had a fight with someone after school...

As for Lao Lin, he should be in the Red Star Welfare Home now, preparing for his after-school tutoring class.

"I've stitched your wound. Remember to ask your parents to take you to the hospital for a tetanus shot." The school doctor gave her wound a final disinfection. "Girls, don't get into physical contact like boys do."

"Thank you, teacher. I want to go to the toilet." Lin Chaoxi looked at his schoolbag on the ground and raised his hand.

Teacher Mei was very alert: "I'm telling you, Lin Zhaoxi, this matter is not over yet. Do you think I won't know anything if you don't say anything?"

Before the head teacher could finish, Lin Chaoxi had no intention of staying any longer. She jumped off the hospital bed, passed between two teachers at a tricky angle, grabbed her schoolbag and ran away.

With the head teacher's roar behind him, Lin Chaoxi ran through the corridor and jumped down the stairs in two steps, completely unafraid of the head teacher's shouting behind him.

Time is running out and she must see Lao Lin immediately.

She began to run madly, the hot wind blowing past her ears. She ran through the campus and the streets. The long whistle sound rose with the wind. Everything was the same as it was seven years ago.

Yes, she really is back.

There is still a chance for everything.

——

Lin Chaoxi rushed to the gate of the Red Star Welfare Home in one breath and stood on the threshold where he had taken a step forward.

There were copper signs with various names on the wall, but there was a small blackboard on the wall compared to when she first came.

On the blackboard was written: Extracurricular Mathematics Tutoring for Primary and Secondary School Students, with an arrow pointing "inward". Lao Lin was always casual, so this arrow was probably his best effort for business.

It was already time for the class to end, and there were many people at the entrance of the welfare house, most of whom were parents who were there to send their children to school. It was very busy and lively.

Lin Chaoxi stood there for a while. It had not been long since she left the Cheese World last time. Why did it look like the threshold of Old Lin's cram school was about to be broken down?

But if this is the case, does Lao Lin still have time to continue his research?

There were many people at the door. When Lin Chaoxi looked around, some parents looked at her from head to toe.

She looked down and saw that the wound on her arm had started to bleed again. The wound was wet from being rubbed with the purple medicine and looked extremely ugly.

She took out her school uniform from her bag, put it on, straightened her clothes, calmed herself down, and walked into the Red Star Welfare Home again.

——

Lao Lin's office is in a relatively dark corner of the welfare home, with no windows or sunlight.

Outside the house there is a camphor tree that blocks out the sun. In early autumn, it blocks out the sunlight, making people feel cool. In winter, it is freezing cold, but this is the place chosen by Lao Lin.

Lin Chaoxi took a step forward and knocked on the door. She probably would never understand Lao Lin's choice in her life.

"Come in."

The sound from inside the door gave her a startle.

Lin Chaoxi pushed the door open and walked in. Old Lin looked up from his books. He seemed younger than he was seven years later.

She couldn't help but recall the scene of her sitting in the noodle shop eating with Lao Lin before she came here.

Old Lin at that time seemed not much different from now. At least she didn't notice anything unusual at that time.

Lao Lin is always relaxed and leisurely. No matter how many things he has been through, the look in his eyes when he asks her "What's up?" is always the same.

She thought she had released a lot of emotions by running wildly just now, but the moment she saw Lao Lin, her eyes still became red.

Maybe it was because she looked a little miserable, her school uniform was dirty, and there must be bruises on her face. Lao Lin stood up, which was rare, walked towards her, and asked again: "What's going on?"

Lin Zhaoxi sniffed: "I had a dream."

"It's more believable if you say you fell down." Lao Lin looked her up and down.

Lin Chaoxi continued to sniff and lowered his head: "Just think of it as a dream when I fell."

"The one about wrestling and dreaming, is that Alice?"

Lin Zhaoxi: “Ah?”

Lao Lin was also stunned: "The little girl who fell into the rabbit hole, could her name be Patrice..."

Lin Zhaoxi: “…”

Still the familiar taste, familiar recipe.

Somehow, in front of Lao Lin, no matter how much emotion she had accumulated before, after Lao Lin talked to her casually, many things seemed like no big deal.

All the excuses she had prepared were no longer effective. Lin Chaoxi thought that she might as well be more straightforward.

"I have a few questions." She sat down in front of Lao Lin with her arms and legs spread out, and then she found a few sheets of draft paper on Lao Lin's desk.

The content above was relatively unfamiliar to her a few hours ago, but now it left a deep impression on her.

That was the proof work related to Lao Lin's graph isomorphism paper. In his spare time, Lao Lin had been doing what he liked to do, but she just didn't pay much attention to it before.

"Please speak." Lao Lin was very polite and made a gesture of invitation.

Lin Zhaoxi came back to his senses: "Do you like Zhen Ji or Da Ji?"

"Zhen Ji."

"Who do you like more, Magneto or Professor X?"

“I like them all.”

"Do you like 'Mimeng' or 'Fried Green Tomatoes'?"

"What is that?"

"What do you think about the problem of graph isomorphism?" Lin Chaoxi asked slowly at last.

Lao Lin: “…”

——

Lin Chaoxi is ready, and after listening, Old Lin will ask her "How did you know that?"

But Lao Lin never plays by the rules. He just asked, "Do you want to hear the part about the isomorphism?"

Lin Chaoxi was stunned for a moment, then realized that this was Old Lin, so he answered very seriously: "I want to hear what difficulties you want to overcome in this issue."

"Oh, I'm more interested in whether the exact graph isomorphism problem is an NPC problem."

Lin Chaoxi decided to play dumb: "What NPC? The kind in the game?"

Lao Lin: “…”

"The full name in English is non-deterministic polynomial complete problem, which is translated as NP complete problem. To trace the origin of this problem, we have to start from the earliest..."

Lin Chaoxi stared at Old Lin. She didn't expect that Old Lin would really introduce her to her seriously. Her father had always told her everything he knew and he was always open and honest.

Lao Lin talked for a while, then, at a perfect moment, he paused and asked, "Why do you ask this?"

Lin Chaoxi could not tell Lao Lin: I came from the future, and I know that you will regret for the rest of your life for not being able to complete this task, so I came to urge you to complete your research as soon as possible.

All she could say was, "Because I peeked at your draft paper and saw that you seem to have been doing this."

Lin Chaoxi observed Lao Lin's expression.

"oh."

Old Lin looked calm, so Lin Chaoxi asked tentatively, "Why don't you finish it?"

As if answering her question, the sound of students bustling about came from the door of Lao Lin's office.

"Teacher Lin, Teacher Lin, class is about to start!"

A few students came running to the door. They were the children from Red Star Welfare School. Some memories of Gao Lin Chaoxi emerged in Lin Chaoxi's mind.

After the results of the senior high school entrance examination came out, all the students in Lao Lin's cram school had excellent scores in mathematics. According to Lao Lin, this was basically normal operation.

But unfortunately, the parent of a child in Lao Lin's class was a reporter, and he publicized Lao Lin's story through the evening paper and news media.

After that, the news that 35 students from the Red Star cram school (a name given by Lao Lin) were admitted to Anning Experimental High School spread throughout the city.

Parents who heard the news swarmed in and collectively broke down the threshold of Lao Lin.

According to Lao Lin's personality, teaching students is not something I will do just because you beg me or pay me, but humans are social animals after all.

One day, the party director of the Red Star Welfare Home knocked on the door of Lao Lin’s office. It was said that someone from higher up had put the connection with the party director.

Lin Chaoxi didn't know what they talked about. After that, Old Lin gave in. After selecting some students that he liked, he recruited a senior elementary school and junior high school class.

From then on, Lao Lin became doubly busy.

Lin Chaoxi sniffed. The children outside the door were excited, as if having math class was a pleasant thing.

If she had never known the future, she would definitely be happy for Lao Lin. But now, she just felt that all these things, including her existence, were wasting Lao Lin's time.

This is not entirely because she must bring back the result of Lao Lin in the Cheese World. It is also because in the timeline of the Cheese World, there is not much time left since Lao Lin's car accident.

This car accident was just one of the causes of Alzheimer's disease. If she was destined to be unable to prevent the car accident, or if Lao Lin was destined to suffer from Alzheimer's disease, she could not let Lao Lin in the cheese world regret it for the rest of his life.

We must seize the time now.

Just as she had finally sorted out her thoughts, the children ran away again.

The wind brought up the smell of the little boy's sweat, and the camphor trees outside the house swayed.

Time seemed to stop suddenly, and Lin Zhaoxi was stunned. She suddenly saw clearly the day when she would leave this world.

December 21st.

Lao Lin had a car accident that day.

Regardless of the outcome, whether she prevents Che Hu from obtaining the research on graph isomorphism problems, she will leave this world.

This is something that is certain, irreversible, and bound to happen.

My heart felt like it was about to explode, but my mind was extremely clear.

Lin Chaoxi raised his head, made up his mind, and said to Lao Lin: "I think you should focus on your mathematics and not let teaching students distract you."

She had prepared a lot of answers to Lao Lin's questions, but Lao Lin asked back: "But it wasn't you who first asked me to teach students?"

"It's me."

Still in a nonchalant tone: "What do you want from Daddy?"

"I want you to do what you should do most, and continue your mathematical research." She emphasized

"What should we do with so many students?"

"You can hire another teacher, and if that doesn't work, I can teach you!"

"Okay, come here." said Lao Lin.

Lin Chaoxi suddenly froze. Wait, what did she just say?

"I feel a little busy recently. As expected, you are my biological daughter, and you know how to share your worries." Old Lin seemed to have put down a heavy burden. He stood up with a book in his arms and patted her shoulder. "Keep going, Teacher Xiaolin."

Lin Zhaoxi licked her lips and suddenly felt that she was being tricked by Old Lin again or something...

Something doesn't feel right.

But she still raised her head and said to Lao Lin: "You must continue to do what you should do. I will check the progress every day!"

"Yes, you are welcome to supervise."

After Lao Lin finished speaking, he picked up the lesson plan and was about to leave. However, after he took two steps, his cell phone rang.

Lao Lin kept walking and answered the phone: "Hello, who is this?"

"Mr. Mei, what's the matter?"

Lin Chaoxi was startled. It was a call from the head teacher.

"I'm sorry to trouble you."

"Okay, I'll try my best to arrange it."

After saying that, Lao Lin hung up the phone and turned back to look at her.

Lin Chaoxi swallowed her saliva. When she sneaked out just now, Teacher Mei seemed to have asked her parents to come to the school.

"My parents have been called. Your teacher Mei will meet with me in my office in half an hour." said Lao Lin.

"Well... then, do you want me to attend your current class right now?" Lin Chaoxi asked tentatively.

"You think too much." Lao Lin dialed another number on his mobile phone and said to her, "After all, this is your criticism meeting, how can the protagonist not be present?"

After that, the call was connected. Lao Lin turned around and asked the person on the other end of the phone: "Hey, are you free later?"

Lin Chaoxi was stunned for a moment. He didn't know who Lao Lin was calling, nor did he know what the other party said. He only heard Lao Lin continue, "My parents have been called. I will be in Teacher Mei's office in half an hour. Please go there for me."

Lin Zhaoxi: “???”