What work can one never finish?

Can you name some countries which do not have the alphabet 'A' in them?

John and his wife were living in a rural place. On a particular day, John's wife fell ill and he called the local doctor. When the doctor picked up, he said, "Doctor, my wife is ill. She might have appendicitis."

"This can't be possible! I took out her appendix two years ago myself," the doctor explained.

When diagnosed, John's wife was found to have appendicitis. How can this be possible?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

Outside a massage parlour, there is a board that reads
"I only massage those who do not massage themselves."

Reading the above statement, does the masseur massage himself?

What is next number in the pattern below:

131 517 192 123 ?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

When can we add 2 to 11 and get 1 as the correct answer?

John has played 50 ODI's and his average is 50. How many runs should he score in his 51st ODI, so that his average score jumps to 51?

I have feet, but no legs. Which animal Am I?