These types of puzzles are known as charades. What you have to do is to find two words that are referred to in the first stanza and the second stanza and put them together to form the third word in the third stanza.

Just for example, if my first refers to 'off' and my second refers to 'ice', then my whole will be the 'office'.

My first is present - future's past -
A time in which your lot is cast.

My second is my first of space
Defining people's present place.

My whole describes a lack of site -
A place without length, breadth, or height.

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

What always comes into a house through the keyhole?

Who has married many women but was never married?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

A man is found dead with a knife in his back When the investigation is done. A chair lays beside him and the forensic team finds moisture around the body.

If he committed suicide, how did he do it?

John was writing his first book. After saving the document, he locked his laptop with a password and mentioned some phrases for the hint box.

A friend of his tried opening his laptop but found out that it was password protected. Following is the hint that appeared.
1 mobile 3 books 2 roars 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches.

Can you help him in cracking the password?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?