What are the subject / verb agreement rules?
OK, let’s start with the very basics. This all might sound very easy, but stick with me because things soon get more difficult!
In English they are 3 types of subject pronouns: 1st Person (when I am talking about myself), 2nd person (when I am talking directly to another person/people) and 3rd person (when I am talking ABOUT people but not directly to them). And, each of these subjects requires a different form of verb.
Now, that all sounds a bit fancy, but actually you learnt this at Beginner level and have been using it ever since (even if you didn’t know it ). Here is a table with the different subject pronouns in English divided by person (who we are talking to / about) and number (how many people we are talking to / about):
| Person | Singular | Plural |
|---|---|---|
| 1st | I | We |
| 2nd | You | You |
| 3rd | He / She / It | They |
So, when we are create sentences, we have to think about which type of subject we have in terms of person and number so that we can choose the correct verb. For example, when you were a Beginner student and studied the verb to be – you learned that you had to use the following forms with the different subjects:
| Person | Singular | Plural |
|---|---|---|
| 1st | I – am | We – are |
| 2nd | You – are | You – are |
| 3rd | He / She / It – is | They – are |
Now, so far you are probably thinking
Shelly, this is super easy! How on Earth can students have problems with this! These are the most basic grammar rules in English!
Well, you’re right, when the subject of our sentence is a pronoun (I, you, he, she, it, we, they), it’s easy to make sure that our verbs agree. But how often in an IELTS essay do you start sentences with she?!!!
NEVER! 
So, you won’t have to worry about PERSON when you write your essay, but you will definitely have to worry about NUMBER. And this is where things get much more complicated.
Singular or Plural Subjects?
In English, subjects of sentences are either SINGULAR (= ONE) or PLURAL (= MORE THAN ONE), and this also affects the type of verb you need in a sentence. Now, in many cases, it is very easy to tell if the subject of your sentence is singular or plural. For instance, I don’t think any of you would have problems choosing the correct form of verb to use in these sentences:
Singular Subject / Verb Agreement
- An employee who works overtime is more like to get promoted than one who doesn’t.
- It is difficult to find a job without work experience.
Plural Subject / Verb Agreement
- Students often find is hard to focus in exams.
- Many children from single-parent families are more independent than their peers.
- Walking and swimming have been shown to help people loose weight, even though they are gentle forms of exercise.
It is rather obvious that the subject it is singular so is used with the singular verb is, and that the subject students is plural so is used with the plural verb find. Maybe the only tricky subject here is Walking and swimming, which is a plural subject because it contains TWO items.
So again, I can hear you shout, where is the problem Shelly??!!!
Well, the problems come with subjects that aren’t OBVIOUSLY singular or plural.