Hello Karen , Comparative is when you compare two persons,objects or anything . In this case the adjective,which describes this comparison will take a certain form : ADJECTIVE + ER ( than ----- ) For example : My car is nice . Karen's car is more nice In this case you will say : Karen's car is nicer than mine . Or just : Karen's car is nicer . Superlative : When you state that a person or an object is holding "super" description in comparison with other persons or objects and it is formed as follows: ADJECTIVE + est For example : In the last example , Karen's car is nicer than mine. Susan's car is even nicer than Karen's . That would make it : Susan's car is the nicest . Another example : My house is big , his house is bigger but Sue's house is the biggest of them all . Present Perfect : It is the tense that describes an action that started in the past and is extended to the present, it is not terminated or has JUST terminated . It is formed as follows : Verb to have + Participate of the verb example : do I have done eat He has eaten He has just finished his work. ( Here the "work" started in the past and is JUST terminated at the moment or a little before the moment he said this sentence. :)

Cherry, that's a great explanation!! I couldn't've done better myself. :-D Brava.