We use these kinds of questions to ask about things that did not actually happen in the past. Remember that "could (not) have + past participle" is always used to talk about things that were or were not possible in the past, but did not actually happen.
- We couldn't have finished if Jon hadn't helped.
(=Really, we finished because Jon helped.)
- If Mark hadn't quit he could have won.
(=Really, Mark quit and he did not win.)
It is also possible to use "could have + past participle" to talk about possibilities in the past. We do not know exactly what happened. We are guessing or giving possibilities.
A) Where is Tina?
B) She could have gone home. Or, she could have gone to the store.
We can use these questions in the same two ways. Could + subject + have + past participle...?
It is also possible to put this in the middle of the question.
A) Could you have come if you weren't sick?
B) Yes, but I was sick, so I couldn't come.
A) Where is Sally? Could she have gone home?
B) It is possible. Sometimes, she leaves work early.
A) Before he left, could he have stolen the report?
B) I don't think that is possible. He is a good guy.
A) Could she have gotten the job if her uncle wasn't the CEO?
B) I don't think so. I don't think she is qualified for the job.
A) Could you have done anything differently?
B) I have thought about it a lot. I don't think I could've done anything differently.
A) If you had studied more, could you have passed the test?
B) Honestly, I don't think so. The test was so difficult.
A) Could anything have been done to prevent the accident?
B) If they had followed the safety regulations, it could have been avoided. Bonus Tips and Points
1. We can use negative questions when we think another person made a mistake and we want to indirectly tell them what they should have done or asked them why they didn't do something.
A) Couldn't you have called me if you knew you were going to be late?
B) You are right. I should have called you. I am sorry.
A) Sorry. I couldn't look over the report last night. I was too busy.
B) Couldn't you have come to work early to finish it?
2. We also make very similar sentences and questions with "would have" and "might/may have". We can use the same sentence and question patterns as we do with "could have".
Real-World English Conversations
- Would you have known that if I hadn't told you?
- Would you have won if she were not on your team?
- He might have gone home or he might have gone out to get some food.
- Jon may have taken the key. I will call him and find out.
A) If I had known that you would be late, I could've slept longer.
B) I'm sorry about that. It took me a long time to get ready this morning.
A) Couldn't you have called me and told me?
B) I didn't think of it. I'll definitely do it next time. Again, I'm sorry.
A) How did you get here?
B) I took a taxi from downtown.
A) Why did you do that? I could have given you a ride.
B) I didn't want to bother you. It was no big deal.
A) Sue was in town last weekend, but she didn't call me.
B) I thought you two were good friends.
A) I thought so too. I know she was busy, but she could have at least called to say hello.
B) You're right. Or she could have at least made a little time to meet and have a coffee with you.
A) What happened to you?
B) I fell down the stairs because I was on my phone.
A) Are you okay?
B) For the most part. I only hurt my arm a little bit.
A) You need to be more careful. You could have killed yourself. Make sure that you pay attention when you are going downstairs and get off your phone! Study these free English lessons to improve your English speaking. If you learn these common sentence patterns well, then your English speaking will improve greatly and you will be able to have fluent conversations in English in the near future! Study the lessons well, practice using them at home and in real life, and make sure to come back to review the material so you do not forget.