Hypothetically speaking, if you were to write about something that might possibly happen in the future, you would use the verb “were” and not the verb “was.”

Incorrect: “I know I would if I w[as] free—only I don’t want to be free.” – Dracula by Bram Stoker

Correct: “Your argument is complete, and if I were free to speak I should not hesitate a moment; but I am not my own master in the matter.” – Dracula by Bram Stoker

Be careful though that you don’t confuse this with the past tense of the verb. A hypothetical set in the past would use the verb “had been.”

Example: “I must have been asleep, for certainly if I had been fully awake I must have noticed the approach of such a remarkable place.” – Dracula by Bram Stoker