We use the present simple to talk about things and situations that are generally true

What is the present perfect tense?
The present perfect tense is a combination of present tense and the perfect (completed) aspect. It refers to an action that either occurred in the past or began in the past but is still continuing. 
How many tenses are there in English?
There are three tenses in English, subdivided into twelve verb patterns (some people call these twelve patterns 'tenses' as well). Past, present, and future tense each contain four subcategories of verb aspects (simple, continuous/progressive, perfect, perfect continuous/progressive). 
What is tense?
Tense is a grammatical term that shows whether an action (or a verb) has happened, is happening, or is going to happen. In other words, tense tells us if something is in the past, present, or future.

2.2 What Is 'Person' in Grammar? (with Examples)

Person is a category used to distinguish between (1) those speaking, (2) those being addressed, and (3) those who are neither speaking nor being addressed (i.e., everybody else). These three categories are called the first person, the second person, and the third person.
In grammar, the personal pronouns (I, you, he, she, it, we, you, they) are grouped into one of the three categories:
The First Person. This category is used for the point of view of the speaker or a group that includes the speaker. A basic sentence in the first person would typically start "I [did something]" or "We [did something]." (In grammar, the first-person personal pronouns are I, me, we, and us.)
Read more the "first person" in grammar.
The Second Person. This category is used for those being spoken to. A basic sentence in the second person would start "You [did something]." (In grammar, the second-person pronoun is you.)
Read more the "second person" in grammar.
The Third Person. This category is used for everyone else. A basic sentence in the third person would start "He [did something]", "She [did something]," or "They [did something]." (In grammar, the third-person pronouns are he, him, she, her, it, they, and them. The third person also includes all other nouns, e.g., Fritz, Germans.)
As well as being categorized as one of three "person" categories, each personal pronoun is also categorized as either singular or plural. Therefore, there are six person categories overall.

The table below shows the pronouns in the six person categories and in the various cases.