Present continuous and Perfect Tense

Present continuous

This tense is used to denote or express some act or action present .thus this tense indicates the going on of some action in the present.

Formation of sentences:

Subject+(am/is/are+1^st form +ing)+Object

Examples:

 I am writing an essay in English.

She is washing the clothes.

They are flying the kites.

The farmer is harvesting the crop of wheat.

We are learning English grammar.

Negative:

Subject+(am/is/are+Not+1^st form +ing)+Object

The farmer is not harvesting the crop of wheat.

 The police are not chasing the thief.

The classes are not being taking by our English teacher.

We are not learning English grammar. 

 Interrogative:

Is,Am,Are+Subject(1^st form +ing)+Object

Are the police chasing the thief?

Are they deceiving the artless people?

Is the government patronizing the intelligent student?

Are we learning English grammar?

The present perfect tense   

This tense is used to indicate or example an action that was begun in the past and completed in the present. It invariably connects a completed event with present.

Subject(has/have+3^rd form)+Object

Examples:

 I have given up smoking.

We have gone to school.

The police has caught the thieves red handed.

Students have learnt tenses in the school. 

Negative:

I have not given up smoking.

We have not gone to school.

The police has not caught the thieves red handed.

Students have not learnt tenses in the school.  

 Interrogative:

Has/have+Subject+(3^rd form)+Object

Have I given up smoking?

Have we gone to school?

Has the police caught the thieves red handed?

Have students learnt tenses in the school?