What can you catch but never throw?

What does this rebus mean?

O
N
C
E
TIME

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

John is looking at Jenifer, but Jenifer is looking at Jacob. John is married, but Jacob is not.

Is a married person looking at an unmarried person ?

Can you decipher the below rebus?

PBLUESAISNUERSES

Can you place six X (crosses) in below board without making three in a row in any way ?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

I add 5 to 9 and get 2. The answer is correct, so what am I?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

You have an empty wine bottle with a cork that has been secured at the top in a normal way. There is a metal ring inside the bottle that is suspended by a string.

How can you make the metal ring drop to the bottom if you are not allowed to touch anything - not the bottle, not the cork, not the thread and not the ring?