SAT Prep - Writing

Verbs are primarily used to describe the action in a sentence, or to describe a state of being.  They describe what the subject of the sentence is doing:

1. I walk (the verb "walk" describes the action of this sentence)
2. I am happy (the verb "am" describes a state of being) 

There are two important characteristics to verbs:

1. Verbs must agree with their subjects
   1. If you have a singular subject, you must use a singular verb form
      1. Singular verbs are formed by adding an 's"  to the verb.  Ex: Kim runs
   2. If you have a plural subject, you must use a plural verb form
      1. Plural verb forms do not have an "s."  Ex: Jim and Kim run
2. Verb Tenses must be consistent
   1. A sentence can't change verb tenses (from past tense to present tense to future tense) unless there is a word signifying a shift of time
      1. Ex: Once, I ran, but now I walk.  There is a verb tense shift in this sentence, from the past tense "ran" to the present tense "walk." but this verb tense is OK because the words "once" and "now" signify a shift in time
      2. Ex: I ran and walk.  There is the same verb tense shift, from "ran" to "walk" but here it is not acceptable because there is no reason for the time shift

Verb tense signifies the time when the action took place.  There are 3 basic verb tenses in English

1. Past tense: For actions that are completed
   
   1. I jumped
   2. The simple past tense is usually formed by adding "ed" to the end of the verb (although there are some verbs with irregular past tenses)
2. Present tense: For actions that are going on right now
   1. I jump
   2. The present tense is just the verb itself
3. Future tense: For actions that will be going on in the future
   1. I will jump
   2. The future tense is usually formed by adding will to the present tense form of the verb
   3. It can also be formed by using am, is, or are with "going to
      1. He is going to sing ("is going to sing" is the future form of the verb "sing")
   4. It can also be formed by using an adverb with the present tense form of the verb.
      1. He sings tomorrow ("Sings tomorrow" is an adverb (tomorrow) that combines with "sings" to create the future form of the verb "sing")