Past modals for judgements and suggestions

When we judge past actions we use:


should (n´t) have

We use should (n´t) have when we give an opinion or judgement about a past situation:

Jessica: I didn´t study for the exam.

Me: You should´ve studied. It was 50 points.

I´m judging Jessica because she didn´t study.

When suggesting alternative past actions we use:

could (n´t) have

would (n´t) have

We use would (n´t) have when we are imagining a hypothetical situation happening to us and doing something different:

Jessica: I forgave my boyfriend.

Me: I wouldn´t have forgiven him.

=

If I were Jessica, I wouldn’t have forgiven him.

We use could (nt´t) have when we are suggesting a hypothetical past possibility:

Jessica: My boyfriend was sad and I didn´t ask him why.

Me: You could have shown more empathy.

=

You had the chance to show empathy but you didn´t.

Exercise 1: modal verbs
Exercise 2: past modal verbs of deduction

Unit 13: That´s a possibility

Past Modals for Degree of Certainty

We can use past modals to  talk about how sure we are that something happened.

The general form for using past modals is:

modal + have + past participle

The charts below demonstrate how to correctly use past modals.

Degree   FACT

Example sentence      

He had a meeting with a client.       

The speaker is 100% sure. This is a fact.

Almost 100% Sure

Comment

He must have had a meeting with a client.     The speaker is making a logical conclusion and is almost sure (but not completely sure) that Mike had a meeting with a client. If Mike always goes to lunch with the speaker unless he has a meeting with a client, then it would be reasonable to say that he must have had a meeting with a client.

Possibility

He may have had a meeting with a client.

He might have had a meeting with a client.

He could have* had a meeting with a client.

The speaker is simply mentioning a possibility here. All three examples in the first column are ways of saying “It’s possible that 

Mike had a meeting with a client.”

Question:  Why didn’t Mike come to lunch with us?

Degree

Example sentence

Comment

FACT

He wasn’t in the office.

The speaker is sure that Mike was not available. This is a fact.

Impossible

He couldn’t have been in the office.

The speaker believes that it was impossible for Mike to have been in the office. Maybe the speaker spoke to Mike right before lunch and Mike said he was 100 miles away visiting a client.

Almost 100% Sure

He must not have been in the office. (not mustn’t have been)**

The speaker is making a logical conclusion. The speaker is 95% sure that Mike was not in the office.

Possibility

He may not have been in the office.

He might not have been in the office. (not mightn’t have been)

The speaker is simply mentioning a possibility here. All three examples in the first column are ways of saying “It’s possible that Mike was not in the office.”

Exercise 1: past modals practice

Exercise 2:  Modals Deduction Past