After reading the information on the parchment, the cat-eared girl asked Zhang Feng curiously:

"Master, what is this black oil?"

Zhang Feng was stunned for a moment, then he spoke thoughtfully: "If I'm not mistaken, the 'black oil' that Shu Daqiang mentioned might be petroleum..."

"What is petroleum, then? Oil that comes out of rocks?"

Windsor was still confused.

"It's a long story. Oil has many uses, but it's definitely a good thing!"

Zhang Feng pinched his chin. If it was really oil, it might provide a lot of help for his subsequent plans.

First of all, one of the most important uses of oil is fuel. Although Zhang Feng already has the mysterious crystal, a clean and pollution-free energy source in another world, this thing is too rare after all, and only he can afford it.

Those noble merchants who had their own steam cars still used wood, coal and other fuels. It was not that they could not afford the mysterious crystal, but that Zhang Feng had no intention of selling it.

If fuel could be refined, it might be very helpful to ordinary people.

Not to mention, besides fuel, oil has many other uses, such as plastics, asphalt, clothing, synthetic rubber, etc.

In other words, if these things are really oil, then Zhang Feng doesn't need to go to the modern world to transport many things, and he can be completely self-sufficient here! This also means that countless wealth is waving at Zhang Feng. Of course, it doesn't matter whether there is money or not. Zhang Feng just wants to protect himself from the threat of the orcs, that's all.

"Then we will be rich, won't we?"

After hearing Zhang Feng's explanation, Windsor's eyes flashed with the shape of money.

"It's not certain whether it is oil or not. It's hard to say. Please write back to Shu Daqiang and ask him to send back some black oil samples."

"Uh-huh!"

Watching the cat-eared girl leave happily, Zhang Feng tapped the table lightly.

If this stuff really was oil, then he would have to be prepared.

After all, it is not an easy task to make use of this oil. First of all, there is the problem of equipment. This thing cannot be produced in the other world for the time being, so we can only buy it in modern times.

Then there is the question of how to utilize oil, which requires refining equipment, which also has to be purchased from Hyundai.

As for more details, we also have to learn from modern times.

then.

Zhang Feng returned to the bedroom and closed and opened his eyes.

The world changes.

In front of me is a minimalist room with a round alarm clock hanging on the warm white wall.

The time showed 5:31 PM, the same time as when I left last time.

When Zhang Feng stood up from the sofa, the aristocratic dress he was wearing instantly turned into casual clothes.

Buzz~ Suddenly, the phone in my pocket vibrated.

Since Zhang Feng basically kept his mobile phone in the storage space when he was in the other world, there was no loss of battery power.

The caller ID shows Lin Yulan.

Answer the phone.

"Zhang Feng, I bought a big fish today and will make pickled fish later!"

The microphone was a little noisy, but the clear female voice could still be heard. Zhang Feng's expression was a little complicated. He said:

"Okay, thank you for your help."

Although in Lin Yulan's view, she and Zhang Feng had only not seen each other for half a day, for Zhang Feng, a whole month had passed.

So psychologically, Zhang Feng always feels a little guilty.

After all, strictly speaking, the time Zhang Feng spent with Lin Yu Lan was not as much as that spent with other people.

However, after Zhang Feng finished answering, the other party fell silent.

"Hey, are you still listening?"

Zhang Feng was a little surprised.

"...Um, Zhang Feng, I... don't know how to make pickled fish..."

After a long time, Lin Yulan's weak voice was heard from the other side.

“…”

Zhang Feng slapped his forehead.

He almost forgot that Lin Yulan was not very good at cooking.

So Zhang Feng had no choice but to say: "Let me do it."

"Yeah, okay!"

Lin Yulan nodded quickly, and Zhang Feng vaguely heard something like "I want the big one".

More than ten minutes later, Zhang Feng opened the door after hearing footsteps in the corridor outside the door.

Lin Yulan, wearing an OL outfit and carrying a black plastic bag, was looking for her keys.

When she saw Zhang Feng opening the door, she subconsciously wanted to throw herself into his arms, but considering that she was holding a big fish in her hand, she held back.

Seeing this, Zhang Feng naturally took the fish and then gently hugged Lin Yulan.

"Hehe, go make the pickled fish, I'll help you!"

"good."

An hour later, Zhang Feng brought a large bowl of pickled fish to the dining table.

There was no particular requirement for the two of us, so we didn't order any other dishes and just started eating.

After the meal, Lin Yulan told Zhang Feng some interesting stories about her work, and Zhang Feng listened quietly.

"Zhang Feng, do you have something to tell me?"

Lin Yulan suddenly spoke with some confusion.

"Uh, there is something I would like to trouble you for help..."

Zhang Feng scratched his head embarrassedly. Every time he encountered trouble, he would come back to Lin Yu Lan for help. After the trouble was solved, he would immediately go to another world. He simply treated Lin Yu Lan as a tool, and he even felt embarrassed.

"You tell me, I can definitely help!"

Lin Yulan wiped her mouth and said another sentence silently in her heart.

If I really can't help, my dad will definitely be able to help! "I want to buy some things, such as drilling equipment, refining equipment, etc., but because I don't have any connections..."

"This is just a small matter!"

Lin Yulan agreed immediately, and then she asked curiously:

"By the way, why are you buying all these strange things? Did you discover an oil field?"

"No, it's just that a friend of mine wants one."

"Oh, leave it to me! I promise it'll be fine!"

Lin Yulan didn't think much about it. She was already used to Zhang Feng's weird behavior.

Now that he is back, Zhang Feng plans to stay for a while longer. Besides the fact that it takes time to buy these things, he also has to learn some basic knowledge.

Otherwise, even if you pass the things over, you won’t be able to use them.

So Zhang Feng started studying.

Because Lin Yulan...his father had a wide network of contacts, Zhang Feng easily bought the relevant equipment and then immersed himself in learning.

Although the seller was surprised that this person spent so much money to buy these things but didn't know anything, he still responded to Zhang Feng's request.

He didn't know if he had mutated, but Zhang Feng felt that he learned things very quickly. Basically, he only needed to be taught once and he would be able to learn it. He could also learn it after reading the instruction manual once.

The teachers who taught Zhang Feng were all amazed by this. If they had not discovered before that Zhang Feng knew nothing about these things, they would have thought that he was some old worker.

During the learning process, Zhang Feng discovered that his storage space had become larger again.

He originally thought that it would take several trips to transport the things over, but the increase in space would save a lot of effort.

In a flash, a month passed and Zhang Feng basically learned everything related to the oil field. Although he had not practiced it much, the knowledge seemed to be deeply engraved in his mind.

Then there is transportation.

Although these tools are very large, Zhang Feng’s storage space is not small either. He can fill one third of them at a time, which only requires three times.

"Hmm? What is this?"

Lin Yulan looked at the green thing that looked like candy beans that Zhang Feng handed over and asked curiously.

"Good stuff, would you like to try it?"

Lin Yulan never doubted Zhang Feng's words and took a bite.

"Hmm~ It's a bit like mint marshmallow..."

Lin Yulan felt that this candy was magical. It melted immediately when she put it in her mouth. It didn’t feel like a solid, but more like a drop of water. It tasted pretty good.

Seeing Lin Yulan putting the food in her mouth, Zhang Feng looked at her nervously. After realizing that there was nothing strange, he felt relieved.

Although he had tried it on a terminally ill patient and found no problem, Zhang Feng was still a little nervous about using it on Lin Yulan.

This thing is the essence condensed from the World Tree of the Moon Shadow Elves.

It is similar to that of the ancient war tree, but the effect is better. The World Tree has only condensed three pills so far, and all of them were given to Zhang Feng.

Zhang Feng took one pill himself, and his physical condition improved a lot without any side effects.

The last time he went to learn about oil fields, he accidentally saw a terminally ill woman who was about to commit suicide. Zhang Feng quickly rescued her, then broke one of the essences in half and force-fed it to the woman. In less than a day, the woman's terminal illness was cured and she was very healthy!

This incident caused a sensation in the country because the woman had been to many hospitals at the time. Those hospitals all had her information, and the judgment was basically that she could only live for a month.

In order not to waste money, her family insisted on her leaving the hospital, but unexpectedly, her terminal illness was gone after she was discharged!

For a while, famous doctors from China and even abroad were rushing here. They wanted to know what happened to this woman. Maybe this could be a Nobel Prize in Medicine! After Zhang Feng confirmed that there was nothing wrong with the woman's body, he quietly slipped away, hiding his merits and fame.

After this experiment, he felt that there should be no problem for Lin Yulan to eat it.

So, what happened today happened. What Zhang Feng gave Lin Yulan was the last complete essence.

"What is this? I suddenly feel like I have endless energy. Could it be..."

As she spoke, Lin Yulan's face suddenly turned red and she lowered her head, not daring to look at Zhang Feng.

"Well, this is just an ordinary health medicine, don't think too much about it!"

Zhang Feng held Lin Yulan in his arms and gently pinched her nose.

After hearing what Zhang Feng said, Lin Yulan felt the same way. Apart from feeling more energetic, she did not experience any of the situations that appeared in the TV novels.

"hey-hey……"

Lin Yulan buried her head in Zhang Feng's chest a little embarrassedly, and then said in a low voice:

"Shall we play games tonight?"

"What game?"

Zhang Feng was stunned.

"I, I bought a cat-ear girl costume. My best friend told me that you men like this..."

Lin Yulan was too shy to raise her head.

"Cat-eared girl, no need for that. It's boring if it's fake. I already——"

Zhang Feng opened his mouth subconsciously, then seemed to suddenly realize something and quickly shut it up.

Lin Yulan raised her head suspiciously.

"Ahem, what I mean is, I like the real you. Don't learn from those slutty bitches!"

Zhang Feng wiped the cold sweat from his forehead.

"Hmph, you are not allowed to say that about my bestie!"

Lin Yulan snorted proudly and didn't think any more about it.

The next day, Lin Yulan got up very early.

Seeing that Zhang Feng hadn't opened his eyes yet, she kissed him gently on the forehead somewhat embarrassedly, then got up to make breakfast.

I don’t know what happened, but when she was playing the two-player game last night, she was particularly energetic. In the past, Zhang Feng always ended the battle victorious, but yesterday, she won for once, which made her feel a little embarrassed.

When Lin Yulan went to make breakfast secretly, Zhang Feng opened his eyes. He rubbed his old waist and said with some emotion:

"The essence of this world tree is fierceness!"

After they had breakfast, Lin Yulan snuggled in Zhang Feng's arms for a while before going to work, and then asked curiously:

"Zhang Feng, what on earth was that thing you gave me to eat yesterday?"

Lin Yulan discovered that ever since Zhang Feng gave her that thing, some changes had taken place in her body. She couldn't tell exactly what the changes were, but they were undoubtedly all for the better.

Zhang Feng was silent for a moment, then replied:

"This is the essence of a huge species called the World Tree. You can think of it as the fruit of the tree. Eating it can improve your appearance, strengthen your body, prolong your life, and prevent diseases..."

"Tsk! I don't believe it. I'm not a child! If you don't want to say it, forget it!"

Lin Yulan kissed Zhang Feng hard on the neck, leaving a red mark, then she put on her high heels and left with satisfaction.

Zhang Feng shook his head.

Woman, you don’t believe the truth and insist on listening to lies!

Looking at the red mark on his neck in the entrance mirror, Zhang Feng thought that he should go to the other world tomorrow, otherwise it would be difficult to explain. Although it would be okay if he didn't have to explain, Zhang Feng didn't want to lie to them.

Zhang Feng is not a scumbag and he would not do anything deceiving. At most he just doesn't tell the whole story.

The next day, after Lin Yulan went to work, Zhang Feng went to the market to buy some small animals.

They are the little rabbit, the little lark, the little turtle, the little fish, the little spider, and the little ant.

By the way, the ant was not bought, but a lucky one he caught from the ground.

Zhang Feng wanted to give it a try. His strength had improved so much and the space had also increased in value. He wondered if he could bring a living creature with him this time.

Instead of putting the animal into the space, I packed it up and put it in my backpack, then took a deep breath and closed my eyes.

Huh~ After coming over, Zhang Feng did not rush to deal with the industrial equipment first, but opened the backpack and checked it from large to small.

Although the little rabbit still had body temperature, it had stopped breathing. Zhang Feng was a little disappointed. But out of respect for the other party's great spirit of dedication to science, Zhang Feng decided to eat a spicy rabbit head in the evening.

Also gone are the lark, the turtle, the fish, and the spider.

“The little ant is actually alive?”

Zhang Feng was stunned. He didn't expect that the weakest ant could survive? Could it be related to its size? Since the ant can survive today, does that mean that rabbits can also survive in the future, and humans can also survive in the future? This is a small step for the ant, but it is a big step for the whole world!

Thinking of this, Zhang Feng became a little excited.

If possible, he certainly hopes that Lin Yulan can come, and he believes that Lin Yulan will not refuse.

Looking at the ant crawling slowly on his finger, Zhang Feng's excitement soon calmed down. The road was still long and there was no time to rush.

Then... he crushed the ant to death.

Biological invasion is unacceptable! Protecting the environment starts with me!