We use this speaking pattern to mean that something was not possible in the past. Subject + could not have + past participle...
- I couldn't have finished earlier because there was too much work to do.
- She couldn't have come because she was sick.
- We couldn't have told her because she wasn't there and her phone was turned off.
- They couldn't have known that because nobody knew except for me.
- Mark couldn't have stolen the documents last night. He was with me all last night.
- I couldn't have done it without your help.
It is very common to use "could not have + past participle" with an if-statement.
These sentences talk about something you really did. But if something had been different in the past, then it would have been impossible to do.
- If Mark had not helped Sue, then Sue couldn't have finished her report.
(Really, Mark helped Sue and Sue finished her report.)
- If she hadn't studied so hard, she couldn't have gotten a 100% on the test.
(Really, she studied hard and she got a 100% score on the test.)
- She couldn't have gotten into that university if her father didn't know the president of the university.
(Really, she got into the university because her father knows the president of the university.)
- I couldn't have bought this house if my parents didn't loan me some money.
(Really, my parents loaned me some money and I was able to buy this house.)
The sentences above are just imagining what could have happened if something had been different. It is the opposite or different than what really happened.
The if-statement can go at the beginning of the sentence or in the middle. Here are more examples.
Bonus Tips and Points
- If I hadn't finished my work, then I couldn't have come to your party.
- If it had rained, then we couldn't have held our annual company barbecue.
- I couldn't have gotten this job if you hadn't helped me.
- She couldn't have known if you hadn't told her.
1. We can also make positive sentences. These sentences show what was possible in the past, but did not actually happen.
- We could have attended the concert if our car had not broken down.
- If they had listened to me, they could've avoided this terrible situation.
- Tim could've died if you hadn't rescued him.
- My boss could have been fired if I had told the CEO what he did.
- If she had prepared more for her presentation, then she could have done a better job.
2. It is possible to use the same sentence pattern with "would have" and "might/may have".
Real-World English Conversations
- I wouldn't have succeeded if it weren't for you.
- She wouldn't have survived if the doctors hadn't done an amazing job.
- They might not have lived if the police had not arrived when they did.
- If I hadn't been in the park that day, I wouldn't have met my wife.
- If she had not been texting, she might not have gotten in the accident.
- If you hadn't lied, your boss might not have gotten so angry at you.
A) I couldn't have gotten this job if you hadn't helped me prepare for the interview.
B) You are my best friend. I was happy to help you.
A) We couldn't have done it without your help. Thank you so much.
B) No problem.
A) I couldn't have believed it before I saw it.
B) I know. It is amazing, right?
A) This project couldn't have been completed without the hard work of every employee in the company. So, I would like to give every employee a bonus to thank them for their hard work.
B) I think that is a good idea and it will be very appreciated by everybody.
A) I think Ben was spreading a rumor about me last week.
B) Why do you think that?
A) I know that Ben doesn't like me and I know that someone was spreading untrue rumors about me.
B) I think it couldn't have been Ben because he was working out of the office all last week.
A) Really? Hmmmm...Use these free English lessons to learn the most common sentence patterns in the English language. If you learn these sentence and questions well, it will help you speak English well. Study the lessons thoroughly, practice making your own sentences, and come back to review often. If you do these three steps, your English speaking will improve quickly and you will be able to have natural English conversations.