This sentence pattern is used to talk about things in the past that didn't really happen.
"Could have" means that something was possible or we had the ability to do something in the past, but really we did not do it.
So, we are just thinking about the past.
It is important to remember that "could" is similar to "can".
Subject + could have + past participle...
- I studied hard, so I think I can pass the test. (The test is tomorrow.)
- If I had studied harder, then I could have passed the test. (The test was yesterday.)
- I could have worked more, but I wanted to go home and see my family.
- He could have come to the party, but he didn't want to.
- We could have won the game if we hadn't made so many mistakes.
- Nobody could have helped us.
- I was so tired that I could have slept on a rock.
- It was so hot I could have died!
It is very common to use "could have" with the past unreal conditional (if-statement in the past tense or past perfect tense). If-statement + (then) subject + could have + past participle...
- If I hadn't been sick, then I could have gone to the party.
(=Really, I was sick and I couldn't go to the party.)
- If it hadn't rained, we could have gone on this wonderful picnic.
- If my car hadn't broken down, then I could have arrived on time.
- If she worked harder, we could have gotten a good score on our group project.
- If they told me that they were coming, then I could've prepared some food.
- If you had told me, I could've helped you.
It is also possible to switch the order of this sentence and put the if-statement at the end.
Bonus Tips and Points
- I could have come if I had I known.
- She could have done better if she had tried her best.
- You could have avoided this problem if you had asked for help.
- Mark could have called if he knew that he was going to be late.
1. We often use "could have" with an unreal conditional. Many times, the if-statement is the past perfect tense. The past perfect tense is "had (not) + past participle".
- If she had not helped, we couldn't have finished all of the work.
- We could have started on time if you hadn't been late.
- If she had prepared more, she could've done better at the job interview.
2. We use the same sentence patterns with "would have + past participle" and "might/may have + past participle".
Real-World English Conversations
- If I had studied harder, I would have passed the test.
- If she hadn't been on her phone while she was driving, she might not have gotten in a car accident.
- If it hadn't rained, I would have gone to the game.
- If he had played on our team, we may have won the game.
A) I lost the race! I feel bad.
B) You could have won if you hadn't tripped at the end.
A) I know. That is why I am so disappointed.
B) It's okay. You will win next time.
A) If she knew she was going to be late, then she could have called.
B) You are right. She should have called.
A) Some people just never think about others!
A) I could have helped you moved last week.
B) I know, but I didn't want to bother you. I know you are busy with work.
A) You should have told me, I would have helped you.
A) I think the plan could have worked if we had done a few things differently.
B) But it didn't work. We failed and we need to accept it.
A) You are right, but we need to learn from our mistakes, so we don't repeat them in the future.
A) How did you get here?
B) I took a taxi.
A) Why? I could have picked you up.
B) I didn't want to bother you. It was no problem.
A) Okay. But next time, call me and I will pick you up. 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.