"Uncle Xu, you are so rich, why do you need to save so much? Anyway, we're fine now, so you don't have to blame yourself! The jar showed generosity, "But if you buy this kind of life-saving thing in the future, you must go through the regular channels!" What he said seemed to be Uncle Xu was the kind of person who bought nine yuan and nine free shipping.

At this time, Cao Fenghua also woke up, and after hearing the words of the altar, he retorted: "These masks are all purchased by me personally, they are absolutely genuine, and there is no problem." ”

"If there's no problem, why doesn't it work?" The jar asked rhetorically.

Professor Jin, who had been holding a gas mask next to him and watching endlessly, spoke: "I may have found the reason why these gas masks did not work!" ”

At this time, everyone's eyes were on Professor Jin.

Professor Jin lit a cigarette and said: "The reason why gas masks can protect against poisonous gases and poisons is that there is a large amount of activated carbon in the masks, which can adsorb toxic and harmful gases or particles, thus playing a role in preventing poisons. ”

"Why doesn't that work?" The jar cried.

"Didn't you say that when you put on a gas mask, you can't smell the pungent stench you used to have?" Professor Jin asked.

I looked at the altar and said, "Yes, it does." ”

"That's what this gas mask does."

"But then ......"

"The reason why the gas masks didn't work later was because the gas that suffocated you wasn't poison gas at all!" Professor Jin said.

"Not poison gas? That...... What is that? "The jar was a little dumbfounded.

"If I'm not mistaken, it's carbon dioxide!" Professor Jin speculated, "Gas masks have no effect on carbon dioxide, so you will still suffocate." ”

"Carbon dioxide? So how can there be so much carbon dioxide in the pool? I asked Professor Jin.

Professor Jin replied, "It may be that the underground gas dissolves in the groundwater, and the groundwater is connected to the pool, which makes the water in the pool rich in carbon dioxide. You all know that carbon dioxide dissolves in water to form carbonic acid, and everyone has drunk carbonated drinks, and we all know that carbonic acid is extremely unstable, and a small disturbance from the outside world will release a large amount of carbon dioxide. If you throw such a big stone into the water, it will naturally cause the water in the waterhole to release carbon dioxide, and there will be a chain reaction, creating a column of air. A large amount of carbon dioxide bursts out at the same time, and the amount of oxygen around you is naturally insufficient, so you will faint due to lack of oxygen suffocation......"

"But what is that foul smell?"

"It smells like hydrogen sulfide, sulfur dioxide...... These are also toxic and harmful gases that are easily produced underground! ”

"I see......" we nodded knowingly.

"I didn't expect you to know so much, Lao Jin, these are all chemistry knowledge, I thought you were not good at science in liberal arts?" Uncle Xu said with a smile.

Professor Jin also smiled: "It is colorless and odorless, soluble in water, but it is unstable and easy to produce gas, and it cannot be adsorbed by activated carbon, so I can only guess carbon dioxide with my knowledge...... After all, like you said, I'm just a liberal arts ...... Of course, I've seen similar cases in a book before, but I just thought of it just now. And ......"

"And what?"

"And all this is just my guess, what the real reason is, we have to conduct on-the-ground scientific investigation and analysis." "Maybe the real reason for the suffocation of this waterhole is that there is something else. ”

Uncle Xu said: "What else is being analyzed? Whatever the reason, we're not going to be near this waterhole again anyway! ”

That night, we didn't eat any fish, so we had to continue to eat our own food. Because I wandered around in the mountains for a day and encountered the pond water in the evening, everyone slept early that night.

Early the next morning, before all of us had even gotten up, we heard a loud noise in the valley next to us. I sat up with the jar, and my first reaction was: "It's the pool!" Which of us is going there again? Before we could think any further, the explosion was followed by a dense burst of gunfire.

Don't think about it anymore, it's definitely our people! There was no one else in the mountains, and even if anyone else came in, it would not have been possible to carry guns with such great firepower as in our ranks.

Tanzi and I put on our clothes and rushed out of the tent, and when we saw Uncle Xu outside, they all walked out of the tent one by one. We simply checked the number of people and found that all the members of our team were there. Then it became clear that someone else had really entered here, and they also owned guns.

Cao Fenghua asked Uncle Xu: "Mr. Xu, I will take two people to explore the situation first." ”

Uncle Xu nodded in agreement and said, "Be careful, the other party has a gun." ”

Tanzi and I also wanted to know what was going on on the edge of the waterhole, so we volunteered to join Cao Fenghua's team. So, the five of us rushed along the mountain road to the vicinity of the waterhole and hid at a distance from the waterhole.

Due to the thick fog on the edge of the waterhole, it is not easy to see clearly. I only vaguely saw that a figure was constantly moving in the fog, and from the sound of "da-da-da" gunshots, there were constantly firelight flying. The flares were supposed to be bullets coming from the muzzle of the gun, but judging by the path of the bullets, it seemed that all the bullets were fired at the waterhole.

At this moment, there were three figures looming in front of us, firing guns and running to the side. One of them, as he ran, threw something out of his hand.

"It's a grenade!" Cao Fenghua said with certainty.

"I'll go, this stupid X, how can I throw a grenade into the pool?" "Don't talk about grenades, every stone thrown yesterday will explode!" ”

As soon as the jar fell, there was a loud bang in the pool, and then the "boom" explosion sounded one after another. The figures fell to the ground after running a few more steps in the fog, only the figure who threw the grenade was still holding on. But just as he took a few more steps forward, a long black shadow broke through the fog behind him, wrapped around the figure like a rope, and then pulled him directly into the fog.

"I'll go, what kind of operation is this, so awesome?" The jar said in surprise.

I smiled wryly and said, "It seems that there is not only a suffocating gas in it, but also a deadly unknown!" ”

By this time, the gunfire had gradually stopped. Listening to the sound, it seemed that some of the people had withdrawn from the edge of the pool, retreating in the other direction of the valley. It seems that there should be more than one entrance to this valley.