Present Perfect Tense

It is used to expressed an action which happened or completed in past but usually the action which happened or completed at a short time before now (near past) not a very long time before now. Specific time such as two years ago, last week or that day is usually not used in the sentences of in this tense. It means that this tense expresses the action whose time when it happened, is not exactly specified but it sounds to refer to some action that happened or completed in near past.

Rules: Auxiliary verb “has or have” is used in sentence. 3rd form of verb (past participle) is used as main verb in sentence.

Structure of Sentence.  
Positive Sentence.
         • Subject + Auxiliary verb + main verb (past participle) + Subject
         • Subject + has/have + 3rd form of verb or past participle + subject
If the subject is “He, She, It, singular or proper name” then auxiliary verb “has” is used after subject in sentence.
If subject is “You, They or plural” then auxiliary verb “have” is used after subject in sentence.
Examples
       I have eaten meal
       She has learnt a lesson

Negative Sentence
        • Subject + Auxiliary verb + NOT + main verb (past participle) + Subject
        • Subject + has/have + NOT + 3rd form of verb or past participle + subject
Rules for using auxiliary verb “has or have” in negative sentence are same as mentioned above.
Examples
      I have not eaten meal.
      She has not learnt a lesson.

Interrogative Sentences
         • Auxiliary verb + Subject + main verb (past participle) + Subject
         • Has/have + Subject + 3rd form of verb or past participle + subject
Interrogative sentence starts with auxiliary verb. If the subject is “He, She, It, singular or proper name” then the sentence starts with auxiliary verb “has”.
If subject is “You, They or plural” then the sentence starts with auxiliary verb “have”.
Examples
      Have I eaten meal?
      Has she learnt a lesson?

More Examples.

Positive Sentences
          They have gone to school
          They have bought a new car
          I have started a job
          It has rained
          The guests have arrived
          John has left for home
          You have told a lie

Negative Sentences
        They have not gone to school
        They have not bought a new car
        I have not started a job
        It has not rained
        The guests have not arrived
        John has not left for home
        You have not told a lie

Negative Sentences                                                        
       Have they gone to school?
       Have they bought a new car?
       Have I started a job?
       Has it rained?
       Have the guests arrived?
       Has John left for home?
       Have you told a lie?