Past Modals in English could have may have might have must have should have would have

Have you ever said, I should have studied, or he might have forgotten? Hi, my name is Elisa, your English teacher, and in this video, we are diving into past modal verbs like should have, would have, must have, and more. You will learn how to talk about regrets, missed chances, and things that almost happened. Let's unlock the secrets of the past in English grammar and make it simple. What are past modals? Past modals are modal verbs like could, should, must. Used to talk about the past, things that did happen, didn't happen, or might have happened. They follow the structure modal, like a modal verb, plus have, plus past participle. For example, could have plus V3. V3 means the verb from the third column or the past participle. May have plus past participle. Might have plus past participle. Must have plus past participle. Should have plus past participle. Would have plus past participle. So, these are the past modals that we are going to work with today. There are a few points that I would like to clarify. Have is always used, not has or had. Could have, may have, might have. Always we should use have, okay? Not has or had. Also, past participle. What is past participle or V3? This is the third form of the verb. For example, eat ate eaten. Eaten is the past participle or V3. Go went gone. Gone is past participle or verb number three. See saw seen. Seen is the past participle. Play played played. Played is the past participle. So, now the question is why use past modals? Why should we use them? We should use them because they help express possibility, probability, obligation, regret, deduction, or criticism. So, if you want to talk about possibility or probability or obligation or regret in the past, you should use past modals. And how you do this, I'm going to explain you step by step. So, first, let's talk about could have, may have, and might have. They can be used interchangeably. It means that you can use could have, or might have, or may have, and the meaning is not going to change too much. So, we use could have, may have, or might have to talk about uncertain possibilities in the past, all right? We are talking about the When you're not sure whether something happened, all three expressions can show possibility and they often mean the same thing. For example, she might have forgotten the keys. We are not sure. So, here we are talking about the past and we are saying that we are not sure if she actually forgot the keys or not. So, it's possible she might have forgotten the keys. She may have forgotten her keys. She could have forgotten her keys. All three mean it's possible she forgot them but I'm not sure, all right? So, here we are talking about the possibility. It's possible that she forgot her keys but I'm not sure 100%. She might have forgotten, she may have forgotten, or she could have forgotten. They all three mean the same thing. Also, you can use could have, may have, or might have to guess about an unknown past action. So, you're guessing what might have happened but there is no certainty. Again, here you are just guessing about an unknown past action. They might have gone to the beach. You are not sure if they actually did go, right? But you're just guessing. For example, you look around the room and you don't see their swimwear, right? So, this way you are guessing that they might have gone to the beach. They may have gone to the beach. They could have gone to the beach. All three mean it's possible explanation but we don't know for sure. So, we are not sure. They might have gone to the beach. We are just guessing. We don't know. Maybe they went to the store or maybe they went to the park. But based on our understanding, we are just guessing that they might have gone to the beach. Now, you should be very attentive when they cannot be used interchangeably. When we cannot use could have, may have, or might have. Could have is used for missed opportunity or ability. Could have is often used to show that someone was able to do something but didn't. Missed opportunity. You cannot replace it with may have or might have in this meaning. Again, if you want to talk about the missed opportunity in the past, you should use only could have. You cannot replace it with may have or might have. That's why in this situation, when we are talking about the missed opportunity in the past, we cannot use may have or might have. For example, he could have won the game if he tried harder. So, the meaning is he had the ability or opportunity but he didn't take it. So, here we are talking about the missed opportunity. He could have won the game if he tried harder. Be attentive. You cannot say he may have won the game. No, no, no, no. That's gonna be wrong. You cannot say he might have won the game. Just forget about it. Only he could have won the game when you are talking about the missed opportunity. Alright, just remember that we use could have when we are talking about the missed opportunity in the past. Let's continue learning about could have. It was possible. I was able to do it but in the end, it didn't happen. I could have gone to the party. It means that I didn't go to the party although it was possible. I had the option but I chose not to. When you have the option to do something in the past and you choose not to do it, you should use could have. I could have gone to the party. She could have taken the job. It means she didn't accept the job even though they offered it. She could have taken the job. She had the opportunity. Alright, she could have taken the job. She had the opportunity. And now we are going to talk about could have and might have. These two can also be used interchangeably in certain situations. You are imagining a negative outcome that was possible but didn't happen and you feel relieved. The car almost hit her. She could have died. It means that she didn't die but it was close. I'm glad it didn't happen. Here we are imagining a negative outcome that was possible. The car almost hit her so it was possible but didn't happen. She could have died. And you feel kind of relieved. You feel relieved that she didn't die, alright, but it was very close. I might have lost my passport but I found it in my bag. You were worried it was lost. Now you are relieved it's not, alright. You were worried about it so you say I might have lost my passport. Also you can say I could have lost my passport but I found it in my bag. Or you can say the car almost hit her. She might have died, alright. So here we are talking about a negative outcome that was possible but didn't happen and you feel relieved. Use could have or might have when you want to say this bad thing was possible but thank goodness it didn't happen. So this is when you should use could have or might have. And now let's talk about must have. So you should use must have first of all when you are talking about the past action. Also you are almost certain it happened based on evidence, logic, or signs. You are making a strong guess, not 100% confirmed but very likely, very close to 100%. I would say 90% guess. She must have left already. Her coat is gone. So here you didn't see her leave but the missing coat is strong evidence. That's why you're sure and you're saying she must have left already. Please be attentive that the action happened in the past. You're talking about the action that happened in the past. Or let's take a look at this example. They must have forgotten about the meeting. No one is here. You are making a logical conclusion based on what you see. So imagine yourself in the meeting room and you see that no one is here. So your conclusion is they must have forgotten about the meeting. They must have forgotten about the meeting. This is a logical conclusion because no one is here. Now let's talk about should have. First, expectation. You expected something to happen but it didn't. In this situation, you should use should have. Use this when you thought something would happen but it didn't and maybe you're surprised. She should have arrived by now. I expected her to be here already but she is not. So here we are talking about our expectation. All right. She should have arrived by now. This is our expectation. I expected her to be here already but she is not. Also, you wish something had been different, specifically when you regret about something. You use should have to say that you or someone else made the wrong choice and you feel sorry about it. We shouldn't have trusted him. The meaning is that we did trust him and now we are sorry about it. We regret that we trusted him. We shouldn't have trusted him. Number three, saying what was better. Your opinion about a better past choice. So you're not always expressing deep regret, right? Sometimes you're just saying what would have been wiser or more appropriate. You should have taken a jacket. It's cold outside. It means that you're not angry, just saying that it would have been a good idea to take a jacket. You should have taken a jacket because it's cold outside. All right, and now let's talk about would have. Use would have to describe a past action that didn't happen but could have in a different situation. So first of all, the situation is imaginary, it's not real, and it's often used for regret or guess what happened in the past. All right, for example, I would have helped you, but I didn't know you needed me. I would have helped you, but I didn't know you needed me. So in this situation, I didn't help, so this is a real past, but if I had known, I imagine I would have helped. But here we want to talk about the imaginary situation. I would have helped you. In reality, you didn't help, but you are saying that I would have helped you, but I didn't know you needed me. And now be very attentive. You should use would have in third conditional. So you understand that you should use would have when you're talking about unreal past. It means that the sentence structure should be like in third conditional. It is actually a third conditional. When you use the past modal would have, you're actually using the third conditional sentence structure, which is used to talk about imaginary or unreal situations in the past. By the way, I have a full video lesson about conditionals, zero conditional, first conditional, second conditional, third conditional, and the mixed conditional. If you would like to learn more about conditionals, feel free to check it out. So now let's talk about would have and third conditional, obviously. Use when talking about imaginary situation in the past, things that didn't happen. As you know, or maybe now you will just learn it, that conditional sentences have two parts, the condition and the result. To build the third conditional sentence, you should follow this structure. If plus past perfect in condition, and would have plus past participle. If I had studied harder, if I had studied harder, if plus past perfect, I would have passed the exam. I would have. Here we use would have passed. This is our past modal, right? Would have. We are talking about the imaginary situation, because in the reality, he didn't study hard and he didn't pass the exam. But he imagines and he says, if I had studied harder, I would have passed the exam. Let's take a look at this example. If she had left earlier, she wouldn't have missed the train. Alright? This is the imaginary situation. Would not have missed. But in reality, she left late and she missed the train. But we say, if she had left earlier, she wouldn't have missed the train. But this is something that didn't happen. Again, if you want to understand how to use all conditionals in English, please watch my detailed video lesson about it. And in this lesson, we learned how to use the following past modals. Could have, may have, might have, must have, should have and would have. Please write down your examples in the comments below. I'm going to read them and get back to you. Great job! Thank you for learning English with me. If you enjoyed this lesson, please remember to like it, subscribe to my channel and leave your comments below. And of course, I'll see you in my next videos. See you soon. Take care.