After finishing the first one, I started to chew on the second mathematics book also produced by Princeton University.
As a world-famous institution of higher learning, Princeton’s attainments and level in the field of mathematics are far ahead of MIT and on par with the University of Cambridge. The library of Peking No. 4 Middle School has purchased a considerable number of foreign high school textbooks and books, of which Princeton occupies the leading position. Most of it.
There is a saying that after Yu Hua read the mathematics books published by Princeton, he had to sigh that the books published by the top famous schools have high gold content.
"Whoa whoa whoa whoa."
There was a constant sound of turning pages, and many students frowned when they heard the sound. They were speechless when they saw Yu Hua turning the pages like a madman.
Damn, is this called reading?
It's obviously just for fun!
Even Lin Wan had to raise her head when she heard the noise. She looked at Yu Hua, who was looking attentively but kept flipping through the book. He glanced at the math questions inside and found them interesting. He smiled and turned back to continue studying.
Time passed, and by ten o'clock in the evening, Yu Hua had finished reading three mathematics books, and his mathematics level had been greatly improved.
Five books, two mathematics textbooks, and three mathematics books.
"It's time to go, let's continue tomorrow." After finishing the third math textbook, Yu Hua withdrew from his highly focused study state, feeling faint in his head. This was a reaction to overuse of the brain, and he felt a little dizzy. He raised his watch. Looked at the time.
When this feeling comes from your head, it means that you have reached your limit and it is impossible to continue learning.
There is no point in learning by force.
Time, 10:05 pm, efficient study time increased from six hours to eight hours.
Feeling confident, Yu Hua closed the book, packed his things and stood up. Seeing that Lin Wan was still studying English, he left without disturbing her.
…
Inside the dormitory.
The kerosene lamp burned slowly, releasing a dim light.
Yu Hua held the wire in one hand and a knife in the other. He carefully peeled off the plastic skin to reveal the copper core inside, and then wrapped the copper core around the positive pole of the small inverter.
Surrounded by roommates, Liu Tao, Zhou Yuan, Ji Han, Cheng Youping and Cao Wei were all attentive, staring at Yu Hua and the portable lighting power supply equipment on the table, not daring to breathe.
After three days of waiting, today, taking advantage of the weekend, Ji Han finally came back with this set of lighting power supplies worth twenty yuan. After Yu Hua came back from the library, he was pulled by everyone to make lighting power supplies.
The two most valuable parts of the entire set of accessories are the battery and inverter, as well as light bulbs, switches and wires, all of which are provided.
"Bring me a Phillips screwdriver." After connecting the positive terminal of the inverter, Yu Hua turned to connect the battery, peeled off the plastic skin to expose the communication, wrapped the positive terminal of the battery like a cat and a tiger, and shouted.
Liu Tao, who was the closest, hurriedly handed over the cross screwdriver, and Yu Hua took it and tightened the battery screws. After solving the positive electrode and the negative electrode, he completed the equipment at the end of the device. After that, Yu Hua arranged the position of the light bulb and installed it in the middle of the dormitory.
After a while of clanking, the wire layout was completed and the 100W incandescent bulb was installed.
everything's ready.
Yu Hua wiped his sweat, smiled at everyone, left a seat, and motioned to the light switch: "Who will be the first to turn on the light?"
The five roommates looked at each other, covered their right hands together, held the light switch together, and looked at Yu Hua.
Seeing this, Yu Hua smiled, stepped forward, turned on the inverter switch, adjusted it to the corresponding mode, and put his hands on the back of Cao Wei's hands.
"Da!" A crisp and short switch sound came out, and the next second, the incandescent light bulb installed at the top of the dormitory was powered on and activated, emitting bright and dazzling light. The dormitory was bright, and there was no longer a dim scene like a kerosene lamp.
"Buzz!"
The sound of the inverter working stably came out.
"Haha, I'm waiting for the light!" Feeling the light from the incandescent lamp above his head and being in a bright environment, Liu Tao couldn't help being surprised and shouted loudly.
Light!
The light that symbolizes hope comes from the light of electric lamps.
The meaning of light is not trivial. To put it simply, they can read and study in their dormitories, no longer having to endure dim kerosene lamps, and no longer having to suffer the pain of myopia.
On a larger scale, the light of electric lights symbolizes civilization and progress, rather than backwardness and ignorance.
"I'm waiting for the light!" Zhou Yuan and the other four were extremely excited. Bathed in the light, they couldn't help but hug Yu Hua tightly.
Everyone was as happy as fools, and Yu Hua was a little relieved and a little sad. The so-called portable lighting source in front of him actually had no technological content. The difficulty of research and development was just to assemble it. In future generations, it would be ordinary, even if it was a useless person. Well-educated middle-aged people will pick it up.
But in this era, this set of portable lighting sources has been labeled as 'advanced', symbolizing civilization and technology.
Of course, it is not strictly correct to say that there is no technological content. After all, batteries, inverters and other components are all the crystallization of knowledge and the embodiment of technology.
"Quiet, everyone, keep quiet. Did everyone learn what I did just now?" Yu Hua signaled everyone to be quiet. After everyone suppressed the excitement in their hearts, he asked.
Everyone looked at each other, nodded, and said in unison: "I learned it." Just now, everyone in the city watched Yu Hua's process of assembling the lighting source. The whole process was very simple, and could be completed by just copying the cat and the tiger.
After just one round of observation, everyone learned how to assemble this advanced portable lighting source.
Yu Hua nodded and said, "That's good. I have an idea. I don't know whether I should talk about it or not."
"Why should Yu Hua be like this? We are classmates and sleep together. If you have any ideas, just feel free to do so." Liu Tao said bluntly.
The rest of the people nodded.
"I want to make a small fortune by relying on this portable lighting source." Feeling the attention from everyone, Yu Hua did not hide it and directly revealed the hidden thoughts in his heart.
make money.
Making a small fortune by relying on this portable lighting source that is so simple that it can be copied at will was Yu Hua's idea from the beginning, but he never said it.
"What do I mean? Of course there is no problem. However, classmate Yu Hua, the cost of a set of portable lighting source components is 20 yuan. This is the family relationship of classmate Ji Han. It is difficult for ordinary people to accept it. The rich The noble family doesn't like it..." When Liu Tao heard Yu Hua's idea, he didn't object. He put himself in Yu Hua's shoes and thought about it. After thinking about it for a while, he couldn't help but frown slightly.
The price of a complete set of portable lighting sources is undoubtedly expensive. The cost alone reaches 20 yuan, not counting the electricity bill. The price is so expensive that ordinary people cannot afford it.
But they look down on the rich and noble people. They live a luxurious life, and a chandelier can be worth hundreds of thousands of dollars.
If you can't achieve high, you can't do low.
"I won't sell it to ordinary people, or to rich and noble people, I will only sell it to you." Yu Hua responded with a slight smile.
