How to use "floors" in a sentence

Now demolished, number 29 was an old building with three floors

Most of them had at least forty floors above ground - these were called "sky apartments." Below ground, there were often another ten floors, for "earth apartments." The government had started building under the ground long ago, because the land inside the city was so limited.

the floors passed by so quickly

nine floors down, she stepped out into a different world

White tile floors

The doors slid open three floors below the surface, on the next to the last level.

When the smoke had begun to settle, it stayed quite close to the ground so that even fifteen metres up in the air, on the roots and upper floors of houses and in high trees, there was a chance of escaping its poison