Riddle 

Easy

1. How many letters are in the alphabet?

2. What has a face and two hands but no arms or legs?

3. There’s a house. One enters it blind and comes out seeing. What is it?

Medium

4.

As I was going to St. Ives,
I met a man with seven wives,
Each wife had seven sacks,
Each sack had seven cats,
Each cat had seven kits:
Kits, cats, sacks, and wives,
How many were there going to St. Ives?

– 18th Century England

5. What instrument can you hear but never see? 

Hard

6. What occurs once in a minute, twice in a moment and never in one thousand years?

7. Which letter of the alphabet has the most water? 

8. What five-letter word becomes shorter when you add two letters to it?

9. What word begins and ends with an E but only has one letter?

10. I am a word. If you pronounce me rightly, it will be wrong. If you pronounce me wrong it is right. What word am I?

https://www.fluentu.com/blog/educator-english/riddles-for-esl-students/