Answer:
What word has kst in the middle, in the beginning, and at the end?
From house to house I go, sometimes narrow, sometimes wide. Whether there's rain or snow, I always stay outside. What am I?
I go up and never come down no matter how hard you wish. As I get higher more wrinkles crawl onto your face.
I am the book one can never finish reading
What belongs to you but others use it more than you do?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.