Each of these modals has a slightly different meaning. We’ll look at each of them using examples from movies and popular songs.

​Could have

We’ll start with could have. Could have means that something was possible in the past, but it did not happen.

I could have gone directly to college, but I decided to travel for a year.

Listen to this song by 1980s teen pop star Tiffany. The singer is thinking about past possibilities with her lost love.

Could have been so beautiful
Could have been so right
Could have been my lover
Every day of my life

Native speakers often do not pronounce their past tense modals as clearly as Tiffany. Could have been usually gets contracted to could’ve been or even coulda’ been.

Listen to Marlon Brando in the classic film “On the Waterfront.” Brando’s character, Terry Malloy, was once a promising young boxer.

“You don’t understand. I coulda’ had class. I coulda’ been a contender. I could have been somebody—instead of a bum.”

To form the negative with these modals, use not between could and have. Could not have means that something was impossible in the past. For example:

She could not have been on that flight because I just saw her at work.

Defense lawyers often use could not have to argue for a client’s innocence.

A popular compliment in English is, “I couldn’t have said it better myself.” You can say this when you like the way somebody said something. It is a way to show strong agreement.

Would have

Let’s move on to would have.

Would have is a bit more difficult because it has two common structures. The first is with but. I would have A, but I had to B. Use this structure to show that you wanted to do something in the past, but you could not.

I would have called, but there was no phone service.
I would have loaned you the money, but I didn’t have any.

Would have also forms the result clause of a past unreal conditional. For example:

If I had known they were vegetarians, I would have made a salad.

You can always reverse conditional sentences. If would have comes first, there is no comma.

I would have made a salad if I had known they were vegetarians.

Past unreal conditionals are very complex; you can learn more about them on a previous episode of Everyday Grammar.

Usually, would have suggests a bad feeling about the past. But not always. In this song by the band Chicago, the singer is surprisingly happy that his ex-girlfriend cheated on him. Her infidelity gave him the opportunity to meet someone else. And that someone else turned out to be his true love.

If she would have been faithful
If she could have been true
Then I wouldn’ta been cheated
I would never know real love
I would've missed out on you

Should have

Finally, let’s look at should have. Should have means that something did not happen, but we wish it had happened. We use should have to talk about past mistakes. A worried mother might say:

“I was so worried about you. You should have called!”

Should have is common in apologies. For example:

I’m sorry that I’m late for work. I should have woken up earlier.

You might remember Lieutenant Dan in the movie Forrest Gump. In the movie, Dan loses both of his legs in the Vietnam War. He would have died, but Forrest saved him.

Listen for should have as Dan confronts Forrest.

“You listen to me. We all have a destiny. Nothing just happens. It’s all part of a plan. I should have died out there with my men. But now I’m nothing but a cripple!”

Should have can be used in a light-hearted way. In this song, country singer Toby Keith imagines how exciting his life would be if he had chosen to be a cowboy.

I should’ve been a cowboy
I should’ve learned to rope and ride
Wearing my six-shooter
Riding my pony on a cattle drive

I couldn’t have said it better myself. As you can see, these modals of lost opportunities offer a colorful way to talk about past choices.