1. Verb Agreement. Verb agreement means you have matched the right verb with the subject of your sentence.  In most cases, your ear will tell you if the subject and verb agree.  Wrong verbs just don’t sound right.
     
2. Inconsistent Tense. Verb tense refers to how you represent time in your speaking and writing.  Events occur in the past, present and future.  There are ongoing events, events that are concluded, and events that are merely possible.  These subtle differences in time and possibility are represented in the verbs you select when you speak and write.  The relationship of one verb tense to another is called consistency.