In a well-constructed sentence, subjects and verbs are linked and must agree; they must match in form, according to person (first, second, or third) and number (singular or plural). In addition, every verb must take the correct tense in the context of the sentence.
Person
A verb must have the same person as the subject.
In addition to agreeing in person, subject and verb must agree in number, which is either singular or plural.
Number
If the subject of a sentence is singular, the verb should be too, and plural verbs should accompany plural nouns.
In the present tense, singular nouns are typically accompanied by verbs that end in “s” (“he runs,” “she plays,” “the man cries”), while plural nouns accompany verbs without an added “s” (“we run,” “they play,” “the men cry”).
Note that the “s” is only added if the subject is singular and in the third person (a noun or “he,” “she,” or “it”); “s” is not added if the subject is “I” or “you.”
Tense
Verb tense provides you with information about when the action took place. Actions take place in the present, in the past, or in the future. Here are some useful verb tenses to learn:
Jenny worked a double shift at the mall yesterday.
Yousef was working at the mall last night when the fire alarm sounded.
Karsa had worked at the mall before she went to college.
Vadim works at the mall after school. (He works there regularly.)
Dabria is working at the mall until 9 o’clock tonight.
Gable has worked at the mall for the last two years.
Pacey will work more hours at the mall next summer.
Tadashi will be working at the mall when his friends begin gathering for his surprise party.
Obrecht will have worked over three years at the mall when he graduates next spring.
Some special verb tenses:
Habitual actions in the past using would and used to: the action took place on a regular basis in the past.
Examples:
When I was a boy, I would buy a root beer float every chance I could.
or: When I was a boy, I used to buy a root beer float every chance I could.
Near future with progressive tenses of go: the action is upcoming relative to past or present.
Examples:
I was going to call you, but I could not find my phone.
or: The girls are going to have dinner before the movie tonight.