Few simple riddles and hard questions

1. How can you make 7 even?
2. What am I?
3. If 1+9+8=1, what is 2+8+9?

 4. How can you drop a raw egg onto a concrete floor without cracking it?      
5. If it took eight men ten hours to build a wall, how long would it take four men to build it?
6. If you had three apples and four oranges in one hand and four apples and three oranges in the other hand, what would you have? 
7. How can a man go eight days without sleep?
8. What often falls but never gets hurt?
9. What is that no man ever saw which never was but always will be?
10. What 3 letters change a girl into a woman?

If u know the answer please comment.