Riddles

1. What runs around the whole yard without moving?
2. What has many keys, but can’t even open a single door?
5. The more of this there is, the less you see. What is it?
6. What is black when you buy it, red when you use it, and gray when you throw it away?
8. What begins with an "e" and only contains one letter?

1. The more you take, the more you leave behind. What am I?
3. What has one eye, but can’t see?
4. Where are the lakes always empty, the mountains always flat and the rivers always still?
6. It stalks the countryside with ears that can’t hear. What is it?
7. My life can be measured in hours, I serve by being devoured. Thin, I am quick. Fat, I am slow. The wind is my foe. What am I?