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.
In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?
You are mixing a mixture of cement and Sand with five gallons of water. You have a garden hose giving you all the water you need. The problem is that you only have a four-gallon bucket and a seven-gallon bucket and neither has graduation marks. Find a method to measure five gallons.
A hen, a dog, and a cat are stolen. Three suspects are arrested named Robin, Steve, and Tim. The police are sure that all of them stole one of the animals but they don't know who stole which animal.
Sherlock Holmes is appointed to identify and is provided with the following statements from the investigation.
Robin - Tim stole the hen
Steve - Tim stole the dog
Tim - Both Robin and Steve are lying. I neither stole a hen nor a dog.
Sherlock is somehow able to deduce that the man who stole the cat is telling a lie and the man who stole the hen is telling truth.
In 2011, people playing Foldit, an online puzzle game about protein folding, resolved the structure of an enzyme that causes an Aids-like disease in monkeys. Researchers had been working on the problem for 13 years. The gamers solved it in three weeks.