Oh no! I've only been a freshman and I've already been targeted by a mean upperclassman.

One minute later.

[Yan Xi: In the third step of the derivation of Gauss's theorem on page seven, you wrote it in divergence form. It's easier to understand using the integral form directly. Divergence won't be on the exam.]

Li Chen turned back to page seven.

She's right.

The divergence form is a higher-order expression, but the exam only requires the integral form. He's used to writing it in a way that's redundant.

He changed it. Re-exported it. Sent it over.

Thirty seconds.

[Yan Xi: This version is okay. When showing it to Wang Qiang, use the integral format. He can't accept the divergent format.]

Li Chen's lips curved into a smile.

She had even calculated what form Wang Qiang would accept.

[Li Chen: Did you also make a study plan for me?]

Fifteen seconds.

A PDF file pops up in the dialog box.

File name: "Li Chen's Final Exam Review Plan_v1.0".

Li Chen clicked on it.

The first page is a timeline. Every hour of every day, from today until the day before the exam, is filled in.

Calculus review sessions were interspersed with Monday, Wednesday, and Friday evenings.

Linear algebra sessions are concentrated on Tuesdays and Thursdays.

The major events should be scheduled during the morning when your energy is at its peak.

Memorizing Marxist philosophy should be done half an hour before bedtime to utilize the memory consolidation effect before sleep.

C programming wasn't in the plan—she knew Li Chen didn't need it.

The second page shows the key points and predicted exam topics for each subject.

The third page contains a table analyzing the types of incorrect questions, with the header stating "Data source: Li Chen's homework and quizzes this semester".

She collected all the error types from his assignments this semester.

Categorized by knowledge point.

The frequency of each error was marked.

Li Chen stared at the third page for a long time.

His finger remained still on the screen.

He turned back to the first page. In the notes section of the timeline, there was a line of small print—

"Every night from 9:30 to 10:00: Rest. You can call me then."

Li Chen locked the screen.

Place the phone face down on the table.

Wang Qiang peeked out from behind the pile of books.

"He's grinning like an idiot again."

"no."

The curve of your lips—

"Wang Qiang."

"Um?"

"Have you finished the third question?"

Wang Qiang shrank back.

Li Chen picked up his phone.

type.

[Li Chen: Received. Also, when did you collect the error analysis on page three?]

Twenty seconds.

[Yan Xi: When you were doing your homework in the cafeteria.]

[Li Chen: You said you were looking at your phone.]

[Yan Xi: I'm taking a picture of your homework with my phone.]

Li Chen's hand hovered above the screen.

Six seconds.

[Li Chen: ...How many copies did you take?]

[Yan Xi: Seventeen assignments. All written assignments you submitted this semester.]

Li Chen slowly leaned back in his chair.

The fluorescent lights on the ceiling were blindingly white.

He raised his hand to block it.

[Li Chen: Yan Xi.]

Yan Xi: Mm.

His thumb hovered over the keyboard for seven seconds.

I deleted it twice.

The third time.

[Li Chen: I'll wait for you at the cafeteria tomorrow at noon. I'll bring you the preserved egg and lean pork congee from that congee shop. You said you wanted to drink it last time.]

Five seconds.

[Yan Xi: Add an order of fried dough sticks. Not too crispy.]

[Li Chen: Understood.]

He locked the screen.

I saved the PDF to my desktop. I also copied it to my cloud drive.

Then I picked up the pen.

Four words were written on the last line of the memo.

"Fried dough sticks, Microsoft."

The Microsoft that is not "Microsoft Corporation".

It has the texture of a fried dough stick—slightly soft, not very crispy.

The kind she likes.

on Monday.

Li Chen's alarm clock rang at 6:45.

The night before, he went through the infinite series in Chapter 5 of Advanced Mathematics according to Yan Xi's study plan. Half an hour before going to bed, he memorized two passages from Marxist philosophy.

When I lay down, my phone showed 11:08.

Today's schedule reads: Morning: Linear Algebra (Matrix Diagonalization + Quadratic Forms), Afternoon: Physics Lab Report, Evening: Advanced Mathematics (Differential Calculus of Multivariable Functions).

The small print in the remarks column remains unchanged.

"Every night from 9:30 to 10:00: Rest. You can call me then."

Li Chen finished washing up and went out. He walked downstairs to the convenience store.

I bought a cup of hot soy milk and an egg pancake. For myself.

Then I took out my phone and ordered takeout.

A clay pot congee shop.

One serving of congee with preserved egg and lean pork, and one fried dough stick.

Note: The fried dough sticks should not be too crispy, and the porridge should be at room temperature, not boiling hot.

Delivery time is set at 11:40 AM. Delivery location: Lobby on the first floor of the Architecture Department teaching building.

After setting it up, he took a bite of the egg pancake and walked towards the playground.

6:58.

News about Yan Xi.

[Yan Xi: Have we arrived?]

[Li Chen: The playground.]

One minute later, she appeared at the track entrance.

Today I'm wearing a navy blue tracksuit. My hair is tied in a high ponytail with a black elastic band, and I'm not wearing a phoenix hairpin.

Li Chen was waiting for her on the third track.

Yan Xi walked up to him and glanced down at him.

"Egg pancake?"

"Um."

"How many bites did you eat?"

"Three people."

"Eat first, then run. Eating while running is bad for your stomach."

Li Chen stuffed the last two bites into his mouth, chewed for eight seconds, and swallowed.

"alright."

Yan Xi didn't move.

She stared at the corner of his mouth for a second.

"There's scum here."

Li Chen hadn't even raised his hand yet.

Yan Xi's fingers had already brushed across the corner of his mouth. Her thumb lightly rubbed it.

Quick and precise movements. The fingertips were cool to the touch.

"Let's go."

She was the first to step onto the track.

Li Chen paused for half a second. Then he followed.

The two maintained a steady pace of six minutes and ten seconds per kilometer. Yan Xi spoke up on the third lap.

"How much of yesterday's plan did you execute?"

"I've finished reading the infinite series in advanced calculus. I've memorized two sections of Marxist philosophy."

Which two sections?

"Chapter Three: The Connection and Development of Materialist Dialectics; Chapter Four: The Essence of Knowledge."

"Finished memorizing it?"

"almost."

"How much difference?"

"I don't remember the last section on the essence of knowledge very well. I need to go over it again."

Yan Xi nodded.

"Recite it again before bed tonight. Repeating it at intervals is the most effective way."

Li Chen responded.

Fourth lap. Yan Xi's breathing rhythm was steady.

"How did you help Wang Qiang with his advanced mathematics?"

"Chapter 3 is finished. Yesterday, I had him do fifteen homework questions. He got nine right. Of the six wrong ones, four were calculation errors and two were due to a lack of understanding of the concepts."

"A 60% pass rate. Not enough."

"I'll explain the conceptual part to him again today."

Yan Xi didn't reply. She ran half a lap.

Where is Zhao Zixuan?

"He said he would rely on intensive training. But his basic linear algebra skills are decent, so it shouldn't be a big problem."

"Chen Mo?"

"Don't worry about Chen Mo."

Yan Xi sped up a bit. Li Chen followed.

After completing the sixth lap, the two stopped at the starting line.

Yan Xi took a rubber band out of her pocket.

Her ponytail had come undone a little. Stray hairs clung to her temples.

She raised her hand, wanting to stab again.

Li Chen reached out his hand.

"I'll do it."

Yan Xi's hand froze in mid-air.

She looked at him for two seconds, then lowered her hand and turned away.

Li Chen took the hair tie. He gathered her loose strands of hair together, threaded his fingers through the base of the ponytail, wrapped it twice, and tightened it.

His fingertips brushed against the downy hair on the back of her neck.

Yan Xi's shoulders tensed for a moment.

"alright."

She turned around and touched the spot where her ponytail was.

"It's tighter than I would tie myself."

"I've practiced it."

"Who did you train with?"

"My mom."

Yan Xi's lips curved into a smile.

"What your mom taught you is quite practical."

"She said she would learn how to use it for her girlfriend."