Reborn, taking my wife to college

Li Changyan first made a mind map of tonight's content, and then started to do the test paper that Lin Yuchen had just given him.

Seeing that Li Changyan was actually doing a math test, Lin Ni became even more certain that they were taking extra classes, but she didn't know to what extent.

Lin Yuchen took out his mobile phone, opened the Baidu network disk, and clicked on the junior high school chemistry knowledge points.

Then take out a blank notebook and give the chemical knowledge a deeper processing.

He still categorized similar knowledge points into 12 categories, namely:

1. Basic concepts

For example, a chemical change: a change that produces other substances.

There are many more, such as physical changes, physical properties, chemical properties, pure substances, mixtures, compounds, oxides, elements, atoms, molecules, ions, catalysts... and so on.

2. Basic knowledge and theory.

比如空气的成分：氮气占78%、氧气占21%、 稀有气体占0.94%、二氧化碳占0.03%，其它气体与杂质占0.03%；

Others include: major air pollutants, chemical formulas of other common gases, common acid radicals or ions, reading and writing chemical formulas of compounds, principles of writing chemical equations, etc.

3. The common name of the substance and its corresponding chemical formula and chemical name.

such as:

Quicklime, calcium oxide: CaO;

Mercury: Hg;

Copper sulfate, blue sulfate, copper sulfate crystals: CuSO4·5H2O;

Sodium nitrite: NaNO2 (industrial salt, toxic);

............

4. The colors and states of common substances.

For example, black solids: graphite, carbon powder, iron powder, CuO, MnO2, Fe3O4▲KMnO4 is purple-black;

红色固体：Cu、Fe2O3 、HgO、红磷▲硫：淡黄色▲ Cu2(OH)2CO3为绿色；

Solution color: All solutions containing Cu2+ are blue; all solutions containing Fe2+ are light green; all solutions containing Fe3+ are brownish yellow, and the rest of the solutions are generally not colorless. (Potassium permanganate solution is purple-red)

............etc

5. Solubility of the substance.

For example, the solubility of salts, the solubility of alkalis, most acids and acidic oxides can be dissolved in water...

6. The best in chemistry.

For example, the hardest substance in nature is diamond, the most abundant metal element in the earth's crust is aluminum, the oxide with the smallest relative molecular mass is water, and the simplest organic compound is CH4...

7. “Three” in junior high school chemistry.

For example, the three types of particles that make up matter are molecules, atoms, and ions.

There are three characteristics of a solution: homogeneity, stability, and mixture.

......

8. “Necessarily” and “Not Necessarily” in Chemistry.

9. Basic chemical reactions: combination reaction, decomposition reaction, substitution reaction, double decomposition reaction, other reactions...

10. Chemical laws: the order of metal activity, the laws of the periodic table...

11. Summary of chemical experiments: common problems, precautions...

12. Problem-solving skills: inference questions, experimental questions, calculation questions...

When Lin Yuchen had sorted out all these knowledge points, the bell for the end of the second evening self-study get out of class rang.

Lin Yuchen put down his phone and stretched. He had been sitting for too long, so he stood up and moved around.

Li Changyan finished the two graphic papers very quickly, finishing one in twenty minutes.

It was finished at 9:35. Seeing Lin Yuchen was immersed in organizing the text, Li Changyan did not disturb him. He used 15 minutes to do a Chinese reading comprehension and excerpted good words and sentences.

Now he stood up, turned around and put the two papers he had done on his desk.

"Achen, I've finished the test paper. Can you help me mark it? Thank you."

"Well, leave it there. I'll take a look later. Have you finished your shower?" Lin Yuchen asked her.

"Yes, I take a shower. I always eat and take a shower right after school in the afternoon. I don't like to wait until the end of evening self-study to take a shower." Li Changyan answered truthfully.

"Yeah, then study for another half an hour and go back at half past ten."

Lin Yuchen sat down and took out a notebook from under Li Changyan's test paper and handed it to her.

"This is the junior high school chemistry knowledge I just compiled. Take half an hour to read it. If you have any questions, feel free to ask me."

After saying that, he picked up the test paper that Li Changyan had just brought over and helped her correct it.

Li Changyan took the notebook handed over by Lin Yuchen, opened it and took a look. At first glance, "The handwriting is really beautiful, but my own handwriting is not bad either, hehe..."

The more I read, the more I admired Lin Yuchen.

"A great author is a great author. The knowledge is well organized and some parts are carefully annotated."

Li Changyan threw himself into studying chemistry as if he had found a treasure, and did not notice at all that his deskmate was hesitant to speak.

Lin Ni looked at the interaction between Li Changyan and Lin Yuchen and felt very envious.

She also wanted to ask the master to help her with her studies, but she didn't know how to ask.

Lin Ni thought to herself, "Why not talk to Chang Yan alone tomorrow and ask her to help me ask Lin Yuchen. Lin Yuchen seems to treat Chang Yan a little differently. Letting Chang Yan speak will give me a better chance of success."

Thinking of this, she packed her things, put on her backpack, said hello to Li Changyan and the other three, and left.

"I'm leaving too, Achen, Xiao Lizi, you guys shouldn't stay too late." Liu Haoran also picked up his schoolbag and left.

Li Changyan and Lin Yuchen: "Yeah, okay."

At 10:20, Lin Yuchen finished grading the two papers. Ninety percent of the answers were correct, but the answers to the big questions at the end were not flexible enough.

"You didn't answer the small questions between the last two questions in these two papers, but the rest are basically fine." Lin Yuchen explained the test papers to Li Changyan and analyzed the reasons.

"I deliberately stacked several layers of knowledge in the last two questions. The fact that you didn't solve them shows that although you have mastered the knowledge, your grasp of it is not solid enough, and you are unable to call upon it at will and apply it comprehensively."

"Later, you can find more big questions to study and see how the questioner adds knowledge points little by little. This will help you to better and flexibly apply the knowledge you have mastered."

"Okay, Achen. I understand now that you put it that way. In fact, I had the same feeling when I did it myself. I seemed to understand it, but when I did it, something seemed not right." Li Changyan was very educated and said that he would do as Lin Yuchen said.

The main point is to listen to advice.

"Okay, if you have nothing else, go back to the dormitory. By the way, is there anything you don't understand about the notebook I just gave you?" Lin Yuchen was conscientious and responsible.

"Well, not yet. I haven't looked at the calculation questions yet, but I have looked at the others, and most of them are still memorized content." Li Changyan synchronized his situation.

"Give me two days. On Thursday and Friday, I will read the content to be memorized several times by myself and memorize it as soon as possible. And as for the calculation questions, can you help me with it on the weekend?" Li Changyan made a request.

"Of course, let's do this for now. Let's go back." Lin Yuchen agreed happily.

"Okay, then I'll take the notebook back and read it." Li Changyan stuffed the notebook into his schoolbag, and then went back to the dormitory building with Lin Yuchen.