what does this picture(rebus) riddle means ?

What occurs twice in a week, once in a year but never in a day?

I can write cow in 13 letters.

Can You?

You order chicken wings at KFC in the boxes of 6, 9 and 20. What is the largest number of wings that you cannot obtain by buying in any combination of the boxes?

What does this rebus mean?

O
N
C
E
TIME

It is always ahead of me yet I can never see it. What is it?

John gave half of the apples he had plus one more to Jacob. He gave half of the remaining ones plus one more to James. Now, John was left with just one apple.

Can you find out how many did he have in the beginning?

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?

If your uncle’s sister is not your aunt, what relation is she to you?

Why is it very easy to weigh a fish?