2025.10.10

The Use of the Past Subjunctive｜Expressing “If …, then … would …”

Izumi

In English, there is a structure used to imagine situations that are different from reality and to say “If …, then … would ….” This is called the past subjunctive.

Although the name includes the word “past,” it does not always refer to the past. The key point is that it expresses a hypothetical situation that is different from the present reality.

In this lesson, I will explain the past subjunctive, which is used to describe unreal situations, along with its grammar points and practical usage.

Contents

1. Basic Rules of the Past Subjunctive
2. Using were with the Verb be
3. Differences in Meaning Depending on the Modal Verb
4. Practical Uses of the Past Subjunctive
5. Summary

1. Basic Rules of the Past Subjunctive

The past subjunctive is used in English when we imagine a situation different from reality and want to express “If …, then … would ….”

The structure is as follows:

If + subject + verb in past tense, subject + would / could / might + base verb

Example:

If I had a car, I would drive to work.

Here, the fact is that I do not have a car. The past tense in the if-clause does not show time, but rather marks an unreal or hypothetical condition.

2. Using were with the Verb be

In the past subjunctive, the verb be is used as were for all subjects, even singular ones such as I, he, she, or it.

If I were you, I would not do that.

In reality, I am not you, so this is hypothetical.

However, in everyday conversation, many speakers—especially in American English—use “was” instead of “were” (e.g., “If I was you”). For formal contexts or exams, using “were” is recommended.

3. Differences in Meaning Depending on the Modal Verb

In the main clause of the past subjunctive, we use would / could / might. Each adds a slightly different nuance:

would → the most common, expresses certainty

If I studied harder, I would pass the exam.

could → expresses possibility or ability

If I had more free time, I could learn Spanish.

might → expresses weaker possibility

If we left now, we might catch the last train.

4. Practical Uses of the Past Subjunctive

4-1. Imagining Situations Different from the Present

If she were here, we could start the meeting.
→ In reality, she is not here
If I were rich, I would travel the world.
→ In reality, I am not rich

4-2. Putting Yourself in Someone Else’s Position

If I were you, I would talk to the teacher.

4-3. Inverted Expressions without if

In formal writing, if can be omitted, and the subject and auxiliary verb are inverted.

Were I you, I would accept the offer.

This form is less common in spoken English but appears in books and exams.

5. Summary

The past subjunctive expresses unreal situations, equivalent to “If …, then … would ….”
The word “past” here does not indicate time, but hypothetical or unreal conditions.
Basic form: If + past tense, subject + would / could / might + base verb
Use “were” for all subjects with the verb be (though “was” is common in conversation).
Modal verbs change nuance:
1. would → certainty
2. could → ability/possibility
3. might → weaker possibility
Inversion without if (e.g., Were I you …) exists, mainly in formal writing.
Differentiate clearly between the past subjunctive (present unreal) and the past perfect subjunctive (past unreal).