Past modals

Past modals are used to express past possibility, necessity, ability, permission, or advice. They help to indicate how an action or event could have been different, or to express a judgment about past actions. Past modals also allow us to make suggestions or comments about past situations that didn’t happen.

1. When Do We Use Past Modals?

To express past possibility or probability: Past modals show that something was possible in the past but didn’t necessarily happen.
- She might have gone to the store, but I’m not sure.
- It could have rained, but we didn’t get wet.
To express past necessity or obligation: Used to show that something was required in the past, but perhaps wasn’t done.
- I should have studied harder for the exam.
- You ought to have called me before leaving.
To express past permission: Used to express whether something was allowed in the past.
- He could have left early if he wanted to.
- I might have helped you, but I was too busy.
To express past advice or suggestion: Used to give advice or comment about what could have been done in the past.
- You should have told me about the problem earlier.
- They could have asked for help if they were struggling.

2. Forming Past Modals

Structure: Subject + modal verb + have + past participle of verb
- She could have gone to the party, but she decided not to.
- I should have called her earlier.

Common Past Modals:

Could have – Expresses past possibility or ability.
- I could have helped you if you had asked.
Might have – Expresses past possibility (more uncertain).
- She might have been at the party, but I’m not sure.
Should have – Expresses past necessity or advice (with a feeling of regret).
- He should have apologized for being late.
Would have – Expresses past intention, but something stopped it from happening.
- I would have gone to the concert if I hadn’t been sick.
Ought to have – Similar to “should have,” .
- You ought to have finished your work by now.

3. Examples

She could have gone to the concert, but she didn’t feel like it. (Past possibility: It was possible for her to go, but she chose not to.)
I should have studied for the exam last night. (Past necessity: I didn’t study, and now I regret it.)
They might have missed the flight, but they arrived just in time. (Past possibility: It was possible they missed the flight, but it didn’t happen.)
You should have listened to my advice. (Past advice: I gave advice that was not followed, and now it’s too late.)