Did you know that there are two common verb tenses for past actions in English? You can use the simple past or the present perfect for a completed past action. So what's the difference? Let's find out together.
To compare the simple past and present perfect, we'll look at how we form these tenses and why we use them. We'll also learn which time markers are used with each tense. Then, we'll see some examples and try some practice to see what you've learned.
Let's start with the form of each verb tense. How do we conjugate the simple past and present perfect in English? For regular verbs, we add"-ed", to the base verb to form the simple past tense.
Whereas irregular verbs undergo various types of changes to the middle, or ending of the verb. In negative sentences and questions, we use the auxiliary verb DID in front of the regular or irregular verb. We form the present perfect tense by using the auxiliary verb HAVE or HAS plus the past participle form of the verb.
HAVE becomes HAS when the subject is HE, she, it, or a singular noun. The past participle of regular verbs is formed by adding"-ed", while irregular verbs change form. In negative sentences and questions, we use the auxiliary verb have or has, depending on the subject.
Now let's talk about the function of these tenses. Here's where it gets a bit tricky. When do we use the simple past and when do we use the present perfect? Both the simple past and the present perfect are used for a completed past action.
The difference is that we know when the simple past action took place, but we don't know when the present perfect action took place. Let's compare these examples. He went to school yesterday.
We know when he went to school. It was yesterday. She has been to Brazil.
We know that she went to Brazil, but we don't know when it happened. Note that the present perfect tense also has another common function, where a past action continues to a present action. But we'll cover that in another video.
Now let's talk about time markers. Since time markers are necessary in a simple past sentence, but not in a present perfect one, you'll see just how important they are to help you distinguish between these two tenses. Time markers are one or more words that show the time when an action takes place.
Common time markers for the simple past include yesterday or the day before yesterday, last and ago. The time marker last is used in expressions such as last week, last month, and last year, while ago is used in expressions like five minutes ago, a few weeks ago, and 12 years ago. We don't need any time markers for the present perfect, since we don't know when the action occurred.
However, there are some optional time markers that we can use to emphasize that an action was completed, and these include already, still, yet, ever, and never. Are you ready to see some examples of these tenses? Here are some examples of the simple past and present perfect in affirmative sentences, negative sentences, and questions.
Let's start with affirmative sentences. She watched a great show on TV last night. The time marker last night means we need a simple past verb. WATCH is a regular verb, so we need to add"-ed". He has read this book.
This sentence has no time marker, so we need to use the present perfect tense. The subject, HE, means we need the auxiliary verb HAS, not HAVE. READ is an irregular verb.
and the past participle is read. For emphasis, we could add the optional time marker already. Moving on to negative sentences.
You didn't call me back yesterday. Yesterday is a very common time marker for the simple past tense. In a negative sentence, we need the auxiliary verb did plus the adverb not to form didn't or did not followed by the base verb call.
Our house hasn't sold. The subject house is a singular noun. So we need hasn't or has not plus the past participle of sell, which is sold.
For emphasis, we could add the optional time marker still or yet. Finally, let's look at some questions. Hmm, I've heard a lot of barking next door. Did the neighbors get a new dog a few days ago? The time marker a few days ago means we need a simple past verb.
We form simple past questions with the auxiliary verb DID and a base verb. Have you been to this restaurant? There's no time marker here, which means we need a present perfect verb. We use the auxiliary verb HAVE when the subject is YOU.
The past participle of the verb BE is BEEN. For emphasis, we could add the optional time marker, ever or yet. Okay, are you ready for some practice? Say or write a simple past or present perfect verb in each of the following sentences. Don't forget to look for the time markers.
Look at the verb in parentheses. Which verb tense do you need? The simple past or the present perfect?
The answer is he didn't or did not play baseball last weekend. There is a specific past time mentioned in this sentence, so we need a simple past verb. Did you remember to use the auxiliary verb did in a negative past sentence? Let's try the next one.
My sister hasn't or has not bought a new car yet. Yep, there's no specific past time mentioned here. The optional time marker, YET, also helps us know we need a present perfect verb in this sentence. Now give this one a try.
Did you get it right? 50 students have registered for this class. We don't know when they registered, so the present perfect tense is correct. Let's try another one.
Here's the answer. Have you ever traveled to South America? There's no specific time mentioned here. It could be at any time in your life. The optional time marker, ever, also helps us know we need the present perfect tense.
Okay, last one. Did you travel to South America last year? You got it! Compared with the last sentence that had no specific time mentioned, now we're talking about last year. This specific time marker means we need a simple past verb.
Great work! Now you know the difference between the simple past and present perfect tenses. See you next time and happy studying!
Ellie