زمان افعال و هماهنگی فاعل و فعل

When writing, it’s important to make sure that your subjects and verbs ‘agree’ with each other. That means that plural subjects should be matched to plural verbs and singular verbs should be matched to singular subjects. If you don’t do this, the sentence is not only grammatically incorrect but confusing to boot.

Let’s look at subject-verb agreement in the present tense.

The valet crash the car. The owners is upset.

Both of those sentences probably look and sound funny to you, but let’s examine why. In the first sentence, we have a singular subject - that’s ‘the valet’ - and in the second sentence, we have a plural subject - that’s ‘owners.’ Quick refresher: to find the subject, first find the verb, and then find the thing the verb is connected to - usually the noun to left of the verb but not always. In the present tense, to make a verb singular, you usually add an ‘-s’ or ‘-es’, while to make a noun singular you remove the ‘-s’.

So, to make the subjects and verbs agree in the first sentence, we would either have to change the subject to make it plural (since the verb is plural) like so -

The valets crash the car. or, more sensibly, change the verb to make it singular by adding ‘-es’, making it -

The valet crashes the car. Likewise, in the second sentence, you must change the form of the verb ‘to be’ to its plural form or change the subject to its singular form, making it either -

The owner is upset. or The owners are upset.

To remember where to put your plurals, think of subject-verb agreement in the present tense as a little bit like a see-saw: When the subject is plural, it gets the plural form (usually an an ‘-s’), and when the subject is singular, the plural drops off the verb and gets the ‘-s’ or ‘-es’ this time.

In the past tense, however, subject-verb agreement is a little less complicated. Why? Because in the past tense, regardless of whether your subject is singular or plural, the verb form stays the same.

So,

The robot menaced me from across the bar.

and The robots menaced me from across the bar.

keep the same verb form, though the first sentence has a singular subject (‘robot’) and the second sentence has a plural subject (‘robots’).

Of course, there are some exceptions! (This is English; there are always exceptions) When certain helping verbs are used as the main verb, then you have to pay attention to your subject-verb agreement again. The most common are ‘has’/’have’ and ‘was’/’were.’ Take this example:

The robot has destroyed the village. Both ‘has’ and ‘robot’ are singular, and ‘has’ is the main verb here. If the main subject is plural, then you must also pluralize ‘have’, as in,

The robots have destroyed the village.

Or, The photo was plastered all over campus. compared to The photos were plastered all over campus. ‘Photo’ - ‘was.’ ‘Photos’ - ‘were.’

When two singular subjects form a compound subject joined by the conjunction ‘and,’ that makes the subject plural, and so, like our earlier examples, you’ll need to make sure your verb is plural to match. Here are a couple of a examples.

The alligator and the crocodile are basically living dinosaurs. Here, ‘the alligator and the crocodile’ is the compound subject joined by ‘and,’ and therefore the main verb is plural - in this case ‘are’ instead of ‘is.’ Let’s look at another.

Laughing nervously, the tourist and his guide wade into the reptile-infested swamp. Here the compound subject is ‘the tourist and his guide,’ and the main verb is ‘wade’ (that’s the plural; remember the singular would be wades, adding the ‘-s’).

As for other conjunctions, ‘or’ and ‘nor’ are also used between two subjects, but instead of bringing them together, they provide contrast - in other words, they keep them separate, singular subjects. In these cases, the subject closest to the verb determines whether it’s plural or singular. So, Neither the band nor the singers are going on tonight. In this case, because the plural noun ‘singers’ is closest to the verb, we use the plural form of the verb - that’s ‘are.’ Switch it around and we need to use the singular. Either the singers or the band is going on tonight. Singular ‘band’ is matched to singular verb ‘is.’

Sometimes your subject isn’t directly to the left of the verb, and this can lead to confusion in subject-verb agreement.

For instance, say you have a prepositional phrase - that’s a phrase connected to a noun by a preposition - that describes something about your subject. In these cases, you have to be careful to identify what the sentence subject is before deciding whether your verb should be singular or plural.

For instance: A team of horses races through the main street daily. Because ‘horses’ is next to the verb ‘races,’ you might be tempted to think the subject is plural - that is, ‘horses.’ However, ‘horses’ is actually part of the prepositional phrase that describes ‘team’ (what kind of team is it? It’s a team of horses). Therefore, ‘team’ is the main subject, and it’s singular, so the verb must be singular to match - hence,

‘the team races.’

Here’s another example: The streets at night are full of dangerous characters. ‘Night’ is to the left of the verb, but the prepositional phrase here describes the streets (what kind of streets? The streets at night), and so the main subject is ‘streets,’ which calls for the plural form of the verb ‘to be,’ which is ‘are.’

Let’s review. Remember that:

Your subjects and verbs always have to agree with each other. Plural subjects should be matched to plural verbs and vice-versa.

Plural subjects usually have an ‘-s’ or ‘-es’ added on to the end of the word, while plural verbs drop the ‘-s’ if they have one. Likewise, singular subjects don’t have an ‘-s,’ while singular verbs do. Remember the see-saw.

In the past tense, your verb tense usually gets to stay the same regardless of the plurality of the subjects.

Helping verbs do have to shift tense in the past tense, however. Most commonly these are ‘has’/’have’ and ‘was’/’were.’

The conjunction ‘and’ helps form compound subjects that should be treated as plural. With the conjunctions ‘or’ and ‘nor,’ however, the tense of the subject closest to the verb tells the verb whether it should be singular or plural.

When faced with a prepositional phrase, remember to go back and find the main subject. That will tell you whether the verb should be singular or plural.