They can't understand the numbers behind these rays, but what alpha rays, beta rays, gamma rays, and neutron rays are, everyone knows more or less, isn't this what radioactive materials are released after decay?

"Mom, there's really radioactive material, run, I don't want to be irradiated!" The grandson was about to run away with a loud voice, but Yu Shengnan grabbed him with his hand.

"Don't worry, listen to me, the detector did detect radioactive materials in it, but these are naturally occurring natural radiation, the dose is very small, and it will not harm the human body.

Saying this, everyone present breathed a sigh of relief.

Han Du waved his hand and said, "Since that's the case, let's go down and have a look." ”

"But do you know where the passage down there is?" Yu Shengnan couldn't help asking.

Han Du's footsteps stopped, ignoring this matter for a while, but he was very energetic now, and said, "What are you afraid of, let's go out and look carefully, we will definitely find it soon." ”

So the five of them left the cave within the cave and divided into different ways to find a passage to the third floor.

But after an hour there was nothing.

They returned to the river, cooked something here, boiled some hot water to drink, mainly because Yu Shengnan was addicted to cigarettes and wanted to find a place to dry wet smoke.

The five of them ate and drank to their heart's content, Han Du, Yu Shengnan, and Sun Zichao sat together and smoked, and Cui Kai and Lao Huang sat on the side to rest.

"Brother Han, I didn't find it, why don't we go back the way we came?" Sun Zichao was idle and urged Han Du to take him away.

"No, I must go down and have a look, since you follow me out on an expedition, just obey the arrangement, don't encourage me to go back the way I came." Han Du blocked Sun Zichao's mouth with a word.

"Think about it, is there anything else we haven't looked for? It stands to reason that there must be a way down, and you see, the water in the huge pool below must have been created by gathering the water of the underground river in the two layers above the cave. "Yu Shengnan is well-informed and has a clear understanding of the structure of karst caves.

Han Du felt reasonable, but after thinking about it, he really couldn't think of any other place he hadn't looked for.

"Woo Woo Woo ......"

Suddenly, when Han Du was depressed, he heard the sound of a dog barking, and he followed the sound and saw the figure of a leopard in a hole not far from the side running out, biting a big red fish in his mouth.

Han Du was overjoyed, he looked for the leopard for a long time along the way, but he never found it, he didn't expect to run out of that hole, he remembered that he had obviously gone in to see it.

"Leopard, where did you run again? Hurt me to look for a long time. ”

Even though Han Du was a little reproachful, he still took the initiative to meet him, and the leopard dropped the big red fish in his mouth, pounced on Han Du and stretched out his tongue to lick him.

The leopard can't understand human words anyway, and Han Du can't understand it even if he is responsible for editing it, so he doesn't talk nonsense, and then he noticed the big red fish that the leopard bit back, and the whole person immediately became energetic.

Isn't this the kind of big red fish in the third level of the pool? It's just that this big red fish looks like it's still underage, only the length of a human arm.

Han Du's eyes immediately looked at the hole in the hole where the leopard ran out, and shouted to Yu Shengnan: "I know where the entrance is, follow me!" With that, he and the leopard ran to the cave first.

Yu Shengnan and the four of them quickly got up and followed, and entered the cave together, Han Du walked very slowly this time, carefully observing the situation on both sides of the cave.

As a result, before he reached the end of the cave, he found that there was a crack in the stone wall of the cave next to him, and the crack in the middle was a little large, so that a dog like a leopard could get into it smoothly, and it would be a little difficult for people to get in.

He squatted down and looked inside, and found that there was something else inside, a large space, and saw that there was an underground river passing inside.

"Han Du, is there a passage here? But the opening is too small, and it seems difficult to get in. Yu Shengnan squatted beside Han Du, squeezed into the gap to look inside, his cheek accidentally rubbed against Han Du's face, and a silky feeling appeared.

Han Du and she both parted their cheeks in an instant and moved to their respective sides, and the atmosphere became silent for a while.

Fortunately, Han Du is not an ignorant little boy in adolescence, just touch it, what's the big deal.

Yu Shengnan was a few years older than Han Du, and he didn't take it seriously quickly, and joked: "You want to take advantage of the old lady, right?" ”

"I ......" Han Du was speechless for a while, you posted it yourself, and you have to blame me.

Then I didn't take it seriously.

Han Du pressed one palm to the edge of the gap in the middle, and after holding his breath and concentrating, he pressed it hard, only to hear a click, and the edge of the mouth instantly cracked, and it was completely shattered by Han Du's palm.

Yu Shengnan knew on the side that Han Du was holding his breath just now, and now he looked at the enlarged gap and exclaimed, "Damn, Han Du, are you using the internal force?" ”

Han Du smiled and said nothing, where did he have any internal strength, he only used his own brute force.

Then, Han Du pressed one palm after another, and the gap continued to expand, and soon expanded to accommodate two people entering at the same time.

He himself was the first to take the lead, with the leopard following and Yu Shengnan following closely.

Sun Zichao and Cui Kai also continued to keep up, and Lao Huang stayed at the back.

Walking in less than ten steps, a rushing underground river appeared in front of them, it is estimated that the leopard's red fish was caught here, it should be the small red fish in the big pool accidentally swam here, the adult big red fish is too big to reach this position.

Han Du walked down the underground river, but fortunately there was still a little place to stand by the river.

Ten minutes later, they finally walked out of this damp and gloomy space and appeared outside in the huge cave space on the third level.

At this point, the underground river continued to flow forward for five or six meters, and finally merged into a huge deep pool, and on the other side, there were two underground rivers, one large and one small, that also flowed into the pool.

In addition, there are three waterfalls more than ten meters wide that fall from the height, and all the water is gathered in a huge pool.

Han Du walked along this giant deep pool, his feet were full of emerald green plants, and the others stood there, like a small sapling compared to the vastness of the deep pool.

"Han Du, if you look at those animals, will they pose a threat to us?" Yu Shengnan was very vigilant, and now he had raised his bow and crossbow.

Cui Kai, Sun Zichao, and Lao Huang also held their bows and crossbows together.

Han Du was thinking about how to cross the center of the waterhole and arrive at the small triangle on the opposite side, forgetting that there were still those strange animals inside, and now judging according to their appearance, he said: "You look at it yourself, the one that looks like a deer should be a variant of some kind of deer, and the one that looks like a mouse should be a variant of a mouse, and it is estimated that there is no aggression, except for those who look like wolves, I guess they are variants of wolves, but because they have lived here for too long, their appearance has changed, so I suggest you attack them as much as you want, Otherwise, we will definitely be attacked by them. ”

This is Han Du's speculation based on the evolution of the red-faced monkey, which is obviously correct, and according to the nature of wolves, they live underneath, even if they become variants, they must still retain the nature of carnivorous animals and have a strong aggressiveness.

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