Which verb form is used to indicate the perfect tense?

Present perfect tense describes an action that happened at an indefinite time in the past or that began in the past and continues in the present. This tense is formed by using has/have with the past participle of the verb. Most past participles end in -ed.

Explanation:

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.