This Question Has Been Taught 12 Times Chapter 4
byLoop 4 (Part 4)
On Sunday, Bai Tong planned to go to Sun Daining’s house in the morning. She had already lowered her expectations for Sun Daining to the absolute minimum—the bare minimum. If they spent the whole day on it, surely she could at least learn the first sub-question.
Bai Tong didn’t tell Bai Jingru until she was almost out the door. Bai Jingru asked which classmate it was.
Bai Tong didn’t want to say and was about to make something up, but Bai Jingru let her off easily, only telling her not to stay at someone else’s house too late.
So Bai Tong left happily.
She had never felt this way before; she was actually looking forward to seeing Sun Daining and was eager to study that problem with her.
Sun Daining opened the door and said in a shop assistant’s tone, “Wel~come.”
Bai Tong’s mood brightened the moment she saw her. “Morning.”
“Morning, have you had breakfast?” Sun Daining asked.
“I have,” Bai Tong replied.
Then Sun Daining led Bai Tong to her bedroom and got straight to the point: solving the problem.
The bedroom window was open, facing the artificial lake in the residential complex. Looking out, the scene was full of life.
Shortly after sitting down, Bai Tong felt it was too noisy. The park-like area outside was swarming with children running around, and birds hidden somewhere in the trees were chirping incessantly.
Bai Tong’s head began to throb, and she said directly to Sun Daining, “Your room is so noisy.”
Sun Daining said, “Is it? I’ll just close the window then.”
She went to close the window. The door was already shut, and as the space became enclosed, a certain fragrance became increasingly noticeable to Bai Tong.
Sun Daining’s room smelled so good.
…It was probably just the scent of laundry detergent or fabric softener, but it was a lovely smell.
She was here to study, so why was her mind already wandering?
Bai Tong didn’t want to ask to open the door again or suggest moving to the study, as that would make her seem high-maintenance. She steadied herself. Three, two, one—class starts.
They had left off at the domain 0 < x = 0 (for 0 < x < 2) became another inequality to solve.
It was very simple now.
By finding the maximum value of -2/[x(2-x)] as -2, she found the minimum value of 'a' to be -2. The first sub-question was successfully resolved.
After finding the answer, Sun Daining looked almost skeptical. "That's it?"
Bai Tong was happy. "That's it. I told you it was simple."
"Wow," Sun Daining was also happy. "This brain doesn't even feel like mine anymore. I guess people really can do anything when they're desperate… hehehe."
They decided to take a break. Sun Daining said she would get some snacks and told Bai Tong to wait in the room.
Bai Tong stood up to stretch and looked around the room. Her gaze was involuntarily drawn to the headboard, where a row of bananas was lined up.
To be precise, they were banana dolls of all kinds. There were standard-looking bananas with arms, legs, and smiles; there were stubby lady finger bananas huddled together like they were fighting; and there were semi-green, unripened fabric bananas coiled like springs.
They were cute, but wouldn't lining them up at the headboard make you feel like a monkey every morning when you woke up?
Bai Tong looked away toward the bed. Sun Daining's sheets were cream-brown, and the duvet was white with embroidered reindeer wearing scarves.
So cute. Bai Tong wanted to reach out and touch the little animals, but felt it might be inappropriate. Just as she was thinking, Sun Daining returned with snacks and yogurt.
"My bed is very comfortable. You can lie down and try it," Sun Daining said, setting the food down.
Really? Would that be okay?
Oh, whatever. She offered.
Bai Tong turned and sat down.
It was indeed very soft.
Then she spread her arms and lay back.
The feel of the bed was secondary; the main thing was the scent—it was wonderful.
Lying there, she was enveloped in a sense of peace.
She asked, "Why do you have so many banana dolls?"
"Aren't they cute? Yin Yi gave them to me. She saw one once and thought it looked good, so she bought it for me. Since then, whenever she travels to different places, she always brings me one. She thinks it's funny."
Bai Tong rolled her eyes on the spot. "…"
What a lunatic. Who thinks banana dolls are cute enough to buy that many for someone?
Out of sight, out of mind. Bai Tong simply closed her eyes.
Then she felt a bit sleepy, and then she fell asleep.
It was like being surrounded by a sea of flowers. She slept deeply until she was awakened much later by a knock on the door.
Opening her eyes, she first saw Sun Daining sitting on the rug by the bed reading a manga, then she saw the reindeer duvet partially wrapped around her like a burrito.
Finally, she saw a person in a sleeveless long dress standing by the door. The woman smiled at them and said, "Shall we go out to eat?"
Sun Daining replied, "Okay, give us a moment."
Then the person closed the door from the outside.
Bai Tong struggled to get up, completely exasperated with herself. How could she fall asleep at someone else's house, on their bed?
"Who was that?" Her manners hadn't fully returned yet.
"My mom," Sun Daining said.
Bai Tong was instantly wide awake. "Your mom is home? Why didn't you tell me?"
"She just got back last night. Is something wrong?"
Bai Tong couldn't really say. Sun Daining added, "Want to go out to eat with us?"
Bai Tong declined politely. "It's too late, I should go home."
Sun Daining checked the time. "It's not even twelve yet. Did you tell your family you'd be back by noon?"
Not really. Bai Tong had thought she'd slept until dinner time; how was it only twelve?
Maybe she should just go with them. It was fine. Bai Tong just had a bit of PTSD regarding anyone with the "mother" attribute; she was a little afraid.
Usually, when her mom came back, she would take Sun Daining all over the city to find beautiful and delicious food.
Before leaving, in the living room, Cen Yu asked what they wanted to eat.
Bai Tong quietly played the role of a mute, but Sun Daining looked at her and said, "What do you want to eat? We'll listen to you."
"…" Bai Tong chose the safest option. "Chinese food is fine."
"Chinese food? Can you eat spicy food?" Cen Yu asked Bai Tong.
"Auntie, I can't handle much spice." If she had to speak to her mother, Bai Tong could only use these very standard, complete sentences, and her gaze never rose above Cen Yu's chin.
Cen Yu laughed. Seeing how nervous and stiff the child was, she wondered if she was really that scary.
She grabbed the car keys and took the two girls out.
In the car, Bai Tong quietly listened to the mother and daughter chat. Their conversation had no specific theme; they just talked about whatever came to mind. At one point, Sun Daining asked her mom if she knew how to find derivatives, and her mom admitted she had long forgotten—or perhaps had never understood it in the first place.
Then they both laughed together.
So Sun Daining took after her mother.
Bai Tong wondered if her own mother knew how to find derivatives. She didn't know. Bai Tong had never asked Bai Jingru about any school problems. Essentially, she didn't seem to know much about Bai Jingru at all.
Listening and daydreaming, they arrived at a bright, airy restaurant by the water. Cen Yu let the two girls order while she took out her phone to make a call.
While ordering, Bai Tong took the chance to observe Cen Yu. She wore a slender watch paired with a simple, narrow white gold bracelet. Her ring was on her middle finger.
She felt Cen Yu looked a bit younger than her own mother, but in terms of beauty, Bai Jingru was still more beautiful.
She didn't know why she kept comparing them. Perhaps Bai Tong was just curious about the role of "mother," whether it was her own or someone else's.
Just as they finished ordering, she saw Cen Yu waving toward the entrance. "Over here."
Another person arrived. Cen Yu had called her best friend over before leaving, likely to prevent the kids from feeling awkward.
During the meal, the adults talked to each other and the kids talked to each other, so the atmosphere was relatively relaxed.
However, the service was incredibly slow. Time seemed to mean nothing; the meal dragged on for nearly four hours.
Sun Daining smiled and told Bai Tong that she and her mom were often like this. Wasn't this what weekends were for?
Bai Tong had never experienced this, but because she was with Sun Daining, the overall experience felt okay.
She had an even more daring thought—it would be nice if she could bring Bai Jingru here next time. She wondered if Bai Jingru would like it, and if she would enjoy being with them.
The plates had long been cleared, and after several rounds of tea, things were winding down. Bai Tong saw that Cen Yu was about to finish her conversation with her friend.
Just then, her phone rang. It was Bai Jingru. It was past five o'clock; her mother was probably anxious. Bai Tong answered and said softly, "Hello, Mom."
Bai Jingru said, "Tongtong, are you coming back tonight or not?"
She was being deliberately sarcastic. Bai Tong joked, "I'm not. I'm never coming back."
Bai Jingru laughed too. "Is the food good? Compared to the food at home?"
How did she know what she was doing? Bai Tong didn't answer.
"I'm coming to pick you up. Tell your friend you have to leave first," Bai Jingru said on the other end of the line.
Not only did she know what she was doing, she knew exactly where she was.
She waited for Bai Tong to hang up. Bai Tong didn't, and neither did she.
Ultimately, Bai Tong didn't want to keep up the stalemate. She ended the call and locked her screen.
This was why she shouldn't have any illusions about Bai Jingru. She was a total freak.