C511 false negative difference

We followed Grandpa Gu and climbed up the cliff. Due to the ancient trees growing on top of the cliff, it wasn't difficult to climb up. Later, I discovered that there were many caves on the wall, and the wind was blowing from these caves. The wind was very cold, slicing at one's body like a knife. It seemed like the cold air of the land of extreme yin came from here.

I asked Grandpa Gu