Give me some english riddles

Questions:
1. What day of the week is the best for having fried foods?
2. What kind of dog has no tail?
3. What keys won't open doors?
4. When can you run as fast as a horse?
5. I begin with T and end with T, and I am full of T. What am I?
6. Why is "heat" faster than "cold"?
7. Why is "SMILES" the longest English word?
8. In CHOCOLATE, there are three things to drink. What are they? (拆字)
9. I get dirty when your face and hands become clean. What am I?
10. Twelve girls were standing under a large umbrella. Why didn't any
of them get wet?
11. What is there between sea and sky?
12. What goes up but never comes down?

Answers:
1. 'Fri'day
2. hot dog
3. monkey, donkey, turkey
4. When I am riding on horseback.
5. teapot (full of 'tea')
6. Because you can catch a cold.
7. Because there is one mile between S and S.
8. COCOA, TEA, and COLA
9. towel
10. A cake of soap
11. It wasn't raining.
12. and (sea 'and' sky)
13. your age

Why there's 13 answers with 12 questions?