Subjunctive mood indicates making a hypothetical statement (i.e. not true).
e.g. If I were you, I would do it. (Past tense for a present action to indicate something contrary to the fact)
e.g. If he were the president, he would do it. (He is not the president, and therefore he will not do it.)
e.g. If you worked hard now, you would pass the exam. (You are not working hard now, and so you will not pass the exam; it is merely an assumption. Compare: “If you work hard, you will pass the exam.” Here, it becomes a condition, and therefore there is a probability that you will pass the exam.)
e.g. If pigs had wings, they would fly. (Pigs do not have wings, and therefore they will never fly.)
Subjunctive mood can also be used in the past tense. In that case, the past perfect tense (instead of the past tense) is used to show the hypothetical statement in the past.
e.g. If he had been the president, he would have done it. (He was not the president, and so he did not do it.)
e.g. If you had worked hard last year, you would have passed the exam. (You did not work hard last year, and so you failed in the exam last year.)
Stephen LauCopyright© by Stephen Lau