🔥EXPLAINED! The Difference Between "I KNOW" & "I DO KNOW" (Advanced English Grammar)

13,008 views ・ 2025-05-29

JForrest English


Please double-click on the English subtitles below to play the video.

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What's the difference between I know  the answer, I do know the answer. Well,  
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they're both correct, but grammatically they're  
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different. I know the answer. Is the  present simple? I do know the answer.
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Is the emphatic form of the present simple?  Today you'll learn everything you need to  
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know about the emphatic form. Welcome back to  JForrest English, of course I'm Jennifer. Now  
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let's get started. Let's review our sentence  again. I know the answer. Of course this is  
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the present symbol. The structure is subject  base verb plus S or ES, and this is used for.
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states and routines, you know that, right?  Now let's review. I do know the answer.  
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This is the emphatic form of the present symbol.  So this sentence is still the present simple,  
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but the emphatic form. The structure is  different. The structure is subject plus  
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do or does conjugated with  the subject plus base verb.
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Now the emphatic form is used to add strong  emphasis to show surprise or contradiction,  
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or to confirm or insist that something is true,  
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especially if someone doubts it. Now don't  worry about taking these notes because I  
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summarize everything in a free less PDF.  You can find the link in the description.
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Now let's review an example where you would use  the emphatic form to add strong emphasis. I could  
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say to you, you've been studying for hours.  You do know the answer, so I'm emphasizing.
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That fact. You do know, you do know. Now,  
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let's review an example to show  surprise or contradiction. I could say,  
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oh wow, you do know the answer. I'm  impressed, or I'm surprised, perhaps.
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And to confirm or insist that something  is true, especially if someone doubts it,  
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this is a very common time to use the emphatic  form. I could say you don't have to believe me,  
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but I do know the answer, so  I'm insisting this is true.
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Now just know grammatically  the present simple is always  
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correct and can be used instead of the  emphatic form. So every example I give  
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you in this lesson, you can replace  the emphatic form with the present.
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Simple, but there is a subtle  difference in meaning between  
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the present simple and the emphatic form.  If I say you've been studying for hours,  
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you know the answer in the present  simple, I'm stating a fact. If I say  
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you've been studying for hours, you do  know the answer. I'm emphasizing a fact.
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Or same thing. Oh wow, you know the answer.  I'm impressed again stating a fact. Oh wow,  
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you do know the answer. I'm impressed, stating  a fact while also showing surprise or that I  
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thought you wouldn't know the answer and that's  the subtle but important difference. Or again,  
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you don't have to believe me, but  I know the answer, stating a fact.
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You don't have to believe me, but I do  know the answer. I'm stating that fact  
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strongly to emphasize it in the face of  doubt. Remember, you're doubting me. Now  
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so far all my examples used the verb no, but  any verb can be formed into the emphatic form.
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Let's review some examples. I do go  there. I, I do go to bed pretty early.  
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I do live in Canada. I do like pizza.  I do write emails every day. I do cook  
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dinner sometimes. But when I do cook,  you know, I'm following a recipe. I do.
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Fix my bicycle when it breaks. I do jump over  fences. I do cry during sad movies. That's  
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true. I do dream big. I do die for coffee, so any  verb you can think of can be used emphatically.
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But just know, only use the emphatic  form if you're adding a strong emphasis,  
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showing surprise or contradiction, or confirming  that something is true in the face of doubt.  
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Use the present simple if you're simply  stating a fact. So if you just ask me,  
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oh Jennifer, where do you live? I would reply  and say, I live in Canada. I'm stating a fact.
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If you say Jennifer, where do you live? and  I say I do live in Canada, it sounds awkward  
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because there's no reason to emphasize this,  but if you say to me you don't live in Canada,  
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well now I can emphasize that something is  true and say no no no I do live in Canada.
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I do live in Nashville, Tennessee.  I think everybody knows that.
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So far all the examples have used.
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The subject I, but remember in the  emphatic form, you need to use do does  
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based on the subject. I do love pizza.  You do love pizza. He does love pizza.  
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She does love pizza. It the dog does  love pizza. We do love pizza. They do.
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pizza. So of course the same rules as the  present simple you use do with I you we they  
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does he she it third person singular. You  already know that it's the same rule as the  
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present simple. So now you know the difference  between I know the answer. I do know the answer.  
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What about these two sentences? I knew  the answer. I did know the answer.
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Well, I knew the answer. Of course this is the  past simple. I didn't know the answer. This is,  
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yes, you got it, the emphatic  form of the past, simple.
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So if you say I knew the answer, of course this  is the pasty. We have subject plus past verb,  
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and this is used of course for completed past  actions. If you say I did know the answer,  
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this is the emphatic form of the  pasty. The structure is different,  
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subject plus did for all subjects plus base verb.
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And this is used for the same reasons as the  present symbol. It's used to add strong emphasis  
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in the past to show surprise or contradiction  in the past or to confirm or insist something  
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was true in the past, especially if someone  doubts it. So the exact same reasons why is  
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just the difference in structure between the  present and the past. So let's review some.
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Realistic sentences. I can say, Yes, you  lifted 50 pound weights. See? You did
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improve. I think you really  did improve night over night.
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So I'm using the emphatic pasty to add emphasis  to a fact. The fact would simply be, see,  
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you improved. That's the pasty to state a fact.
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Or I could say, you did call him. I thought you  forgot. So I'm showing surprise or contradiction.  
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Honey, you did call him back because it's, it's  really old. If I simply say you called him,  
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I thought you forgot. I'm stating  a fact in the past, of course.
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Or if I say I did send the report on time, I'm  confirming or insisting that something was true  
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remember the past, especially if someone  doubts me maybe my coworker or my boss even  
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but if I say I sent the report on time,  I'm just stating a fact about a complete.
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Needed past action. Remember that  in the past simple emphatic form  
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all subjects use the same structure so it's easier  
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and any verb can be formed into the emphatic  form in the pasty just like we saw with the  
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present symbol so you could say I did finish  my homework you did call her last night he.
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Did help with the project. She did find her  keys. It did rain yesterday we did watch the  
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movie they did arrive early. Also keep in mind  the emphatic form that you've just learned exists  
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in the present or past simple affirmative, which  means positive sentences only. So you can't use.
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Emphatic form with perfect tenses, future  tenses, continuous tenses, the negative form,  
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or question form, present simple positive, past  simple positive. Now that you know the rules,  
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quite simple, right? Now that you  know the rules and the structure,  
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let's quiz your knowledge.  You're going to see a question.
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And then you need to answer out loud and  your answer must use the emphatic form.
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And you'll have to look at the question to  decide if you need the present or the past.  
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I'm not going to tell you just to make this quiz  more difficult. I'll only give you 3 seconds,  
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so of course feel free to pause the video,  think about it, and then hit play when you're  
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ready and you can say the answer out  loud. Question 1, you know how to swim?
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The answer, I do know how to swim. You're  emphasizing this and notice my question,  
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almost a statement but said as a question,  
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there's an assumption that you don't know  how to swim or there's surprise in this.  
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So that's why you're using the emphatic.  Question two, did he call you yesterday?
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The answer? Yes, he did call me yesterday. The  question you did, so you know it's the past  
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simple, and I'm emphasizing the truth of this.  Question three, you don't like coffee, do you?
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The answer
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Actually, I do like coffee. You don't need to add  actually or you could say yes, I do like coffee,  
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or you could simply say I do like coffee  and notice in the question again there's an  
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assumption that you don't like coffee. So that's  why you're using the emphatic form. Question 4.
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This might be a little tricky. Feel free to  
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pause. Question 4. It's OK that you  didn't finish the project on time.
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How would you reply?
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I did finish the project on time,  so the question assumes you didn't  
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and you want to correct that by saying  no, I did finish the project on time.
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Question 5, they never help with the cleaning.
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How could you reply?
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They do help they do help with the  cleaning. They do help sometimes,  
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but you could simply say they do help.  So again, the question states that they  
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don't and you want to affirm the opposite,  insist the opposite. They do help sometimes.
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How are you doing with this? Question 6,  
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I think I forgot to lock the  door. We should go back and check.
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What could you say?
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You did lock the door. I saw you.
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You could add that or maybe you say I did lock the  door so you're affirming that you did the action  
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so the person doesn't have to worry. So again  the person assumes that the opposite is true and  
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you're emphasizing, you're affirminguestion  7, does she always come to work on time?
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What could you say?
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Yes, she does come to work on time,  so you're emphasizing that fact.
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Question 8, why don't you eat vegetables?
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You can reply back and say.
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I do eat vegetables or maybe add I do eat  some vegetables. I do eat certain vegetables,  
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so again the questioner assumes you don't  do something and you want to infer affirm  
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or insist the opposite. Question 9, we need to  discuss why you didn't follow the checklist.
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You can reply back to this and say.
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I did follow the checklist. I did  follow the checklist. So again,  
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contrary to what the person believed.
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And question 10, they didn't attend  the meeting last Friday, did they?
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You would say?
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They did attend the meeting, so how do you  do with that quiz? Share your score in the  
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comments and review this again so you  understand the structure of the present,  
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the structure of the past, and when it's  used. And do you want me to keep helping  
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you improve your grammar if you do put  yes, yes, yes, yes, yes, yes, put yes yes.
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Yes in the comments below and of  course make sure you like this lesson,  
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share it with your friends and subscribe  to your notified every time I post a new  
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lesson and you can get this free speaking  guide where I share 6 tips on how to speak  
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English fluently and confidently. You can  click here to download it or look for the  
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link in the description. And here's another  lesson I know you'll love. Watch it now.
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