DIFFICULT RIDDLES

There was a man who was born before his father, killed his mother, and married his sister. Yet, there was nothing wrong with what he had done. Why?

Some will use me, while others will not, some have remembered, while others have forgot. For profit or gain, I'm used expertly, I can't be picked off the ground or tossed into the sea. Only gained from patience and time, can you unravel my rhyme? What am I?

Forward and forward I go, never looking back. My limit no one knows, more of me do they lack. Like a river I do flow, and an eagle I fly. Now can you guess, what am I?

A boy has as many sisters as brothers, but each sister has only half as many sisters as brothers.

How many brothers and sisters are there in the family?

In 2000, a 40-year-old doctor told his son that when a little boy he decided to be a doctor by seeing a internet web site about performing a heart transplant on a puppy with a defective heart so that the puppy would live a normal life. I then thought that I would be a doctor so that I could help people in a similar way. What is the defect in this story?

A prisoner is told "If you tell a lie we will hang you; if you tell the truth we will shoot you." What can he say to save himself?

What is the difference between a school boy studying and a farmer watching his cattle?

What is the next 3 letters in this riddle? o t t f f s s _ _ _

Who spends the day at the window, goes to the table for meals and hides at night?

Marking mortal privation, when firmly in place. An enduring summation, inscribed in my face.

What am I?