"Okay, that's all for today. The voice of the professor in charge of the lecture stopped abruptly in the ringing of the bell that pierced the clouds.

The students' tense scalps suddenly relaxed, or they cleaned up the tables, or they formed groups of two or three

Yan Jiujiu was like a deflated ball, she pillowed her overlapping arms and quietly looked out the window.

"What should I do!" Yan Jiujiu casually blew away the broken hair that had slid to the tip of his nose, and said secretly in his heart.

The branches of the ancient trees outside the window are luxuriant, the lush branches and leaves are printed all over the window, and the light leaves are swaying with the breeze, like a landscape painting living in the window frame, Yan Jiujiu thought silently, his lips crossed the arc outlined by the meteor.

"Qi Xuan?"

Yan Jiujiu squinted through the gap in the leaves to trace the source of the light, the delicate and soft light was like a mother's kind and warm palm, a wave of sleepiness hit, she seemed to be hallucinating.

"Qi Xuan?" O'Henry's voice was genuine and kind.

"Huh?" Yan Jiujiu rubbed his sleepy eyes, "What's wrong, Henry?"

Yan Jiujiu turned around and met Henry's warm eyes, and she smiled faintly.

"Are you sleepy?" O'Henry asked worriedly, "I see you've not been in a good state of mind lately, and you still have a class, why don't I take a leave of absence for you?"

He lifted the strands of hair that fell in front of Yan Jiujiu's face, and a tired and slightly pale face appeared in front of him, and his heart was slightly distressed, only touching the center of his eyebrows.

"There's one more lesson, it's fine. I'll just lie down on the table and rest for a while. Yan Jiujiu shook his head and said with a faint smile.

"You lie on your stomach, I'll tell the teacher later. ”

"Hmm. She nodded, and then thought of something, "Why didn't Victoria come today?"

"She's back in the royal class," O'Henry said lightly, as if he wanted to bring up the topic in one sentence.

"Hmm. Yan Jiujiu didn't associate the events of the previous days with it, she thought clearly in her heart, "For a noble princess like Victoria, compared to a commoner like her, it is different after all." ”

Don't think about these questions now.

She buried her face in the crook of her arm, and muttered in a mosquito-like voice, "What should I do, what should I do, mother, economics is so difficult, well, I don't understand, I don't understand, wow"

"What do you say?" O. Henry poked Yan Jiujiu's arm, "Economics, what's wrong with economics?"

Yan Jiujiu was still immersed in self-pity and self-pity, and he didn't pay attention at all, and only followed O'Henry's words and said, "Economics is so difficult to understand!"

"Where do you not understand?"

"What the hell is that spider web model, why the hell did you invent it, and what kind of depreciation is it!

Yan Jiujiu raised her head suddenly, she looked at the air and was stunned for a few seconds, then turned her head to look at O'Henry, and said, "That and that cough cough"

Ou Henry looked at Yan Jiujiu's cute face, his face was crimson, and he couldn't help but smile: "It's nothing! Economics is a relatively abstract subject, and it often needs to be combined with some reality in learning. He paused, "Because the students sitting here are basically involved in the family business, the teacher is more general, and if you don't know in the future, ask me, and I will sue you." ”

O'Henry's shallow pear vortex once again gave a full score in Yan Jiujiu's impression score, "Thank you!" She was very happy in her heart, "It's good to have such a friend as you!"

Ou Henry only smiled silently, and then seriously analyzed with Yan Jiujiu: "The spider web model you just mentioned is actually an example of a dynamic model, and the analysis of the spider web model involves stable and unstable equilibrium. ”

"Stable dìng equilibrium and unstable dìng equilibrium" Yan Jiujiu blinked his eyes and nodded as if he didn't understand.

O'Henry's face was clear, he nodded, his smile was bright, and he said: "Western economics divides equilibrium into stable equilibrium and unstable equilibrium according to whether the equilibrium state is stable or not. For example, in the case of the equilibrium price model, when the equilibrium price system of the entity is affected and deviates from the equilibrium point, if the system can return to the original equilibrium point under the action of the market mechanism, the equilibrium price system is said to be a stable equilibrium. Then the reverse is not. ”

"Eh" Yan Jiujiu only nodded silently, raised his index finger, and repeated O'Henry's analysis word by word.

Her earnest appearance made O'Henry laugh.

"Hmm. You have to understand the concepts of economics thoroughly, and then you can understand the knowledge points more easily. Because each knowledge point needs these basic knowledge points to build an understanding framework. O'Henry flicked Yan Jiujiu's forehead lightly, and then smiled: "Now that you understand the basic concept, you can analyze the spider web model." ”

O'Henry's expression gradually became serious, "The spider web model examines commodities with long production cycles, and his basic assumption is that the current output of commodities Q depends on the price P of the previous period, that is, the supply function is Q=f(p);and the demand for commodities in the current period Q1 depends on the price P1 of the current period, that is, the demand function Q1=f(p1)." ”

Yan Jiujiu rubbed his head, his index finger stirred his hair, pursed his full pink lips, and his apricot eyes were weird, "That Henry!

She suddenly reached out and covered her cheeks, blinked her eyes, and said, "Your skin is so good, tell me how you take care of it!"

O'Henry was puzzled by her this, and immediately smiled with relief, he cleared his throat and said, "The spider web model is distributed in scattered and closed types."

Yan Jiujiu saw that his trick of changing the topic was recognized, and he lay on the table with a sigh, sighing, and said: "I think these concepts are too far away from me, can they be combined with the reality of life?"

O'Henry smiled helplessly, and said, "I'll think about the case! yes!" He snapped his fingers, and simply put his face on the crook of his arm, and said slowly: "A few years ago, due to storms and bad weather, the yield of potatoes dropped significantly, and the price of potatoes increased. As the price of potatoes rose, farmers expanded their potato plantings, bringing the yield of potatoes to an all-time high two years later. As a result, the significant increase in the supply of potatoes led to a sharp drop in the price of potatoes, which in some areas fell from 10 pence to 1 pence per 0.4536 kg that year, which was even lower than the average cost. And this phenomenon can be explained by the spider web model. ”

Yan Jiujiu suddenly realized: "I see!"

She turned her head sharply, but she didn't expect O'Henry's face to be close at hand, her face turned red into a tomato in a moment's panic, she didn't know what to do, she only felt that her neck was fixed by something, stiff and paralyzed, unable to move, and she felt a trace of coolness on the tip of her nose.

"You really like to blush. O'Henry smiled brightly, revealing half a row of neat white teeth, "In science, this is called reflex ** sensory nerve excitement, increased secretion of catecholamines such as norepinephrone hormone, resulting in telangiectasia, and blushing." ”

He smiled with a pretended satisfaction, "Hmm." This shows that you care more about me. He nodded and said something funny, "I like it." ”

“”

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Thank you for your support and companionship!I hope that the treasures who like this book will collect more, I like to be unexpected, and I also hope to bring unexpected surprises to everyone. Thanks!^o^)