Course paper on theoretical grammar

How to conjugate verbs in English

Using verbs isn’t as easy as just tossing them in a sentence. They need to represent the tense you want, as well as match the subject (subject-verb agreement, explained below). This is called verb conjugation, or changing the verb to fit the sentence. In English, there are four main tenses, each divided into three time periods, totalling twelve tenses. Some other tenses exist, but these are the most common ones. 

Main tenses:

• 
  simple
  
• 
  continuous
  
• 
  perfect
  
• 
  perfect continuous
  

Time periods: 

• 
  present
  
• 
  past
  
• 
  future
  

Below, we explain how to conjugate each of the main tenses in the present, past, and future. Keep in mind that irregular verbs may use different forms. 
Subject-verb agreement
No matter what tense you use, your verb has to match the number of the subject. In other words, singular subjects conjugate verbs differently than plural subjects. 
A lot of the time, you either add -s to the end of the verb or you don’t. However, more advanced tenses with auxiliary verbs can get tricky—both be and have are irregular verbs, so you have to pay close attention to using their right forms even when they’re not the main verb.