English has four “perfect” verb forms, each of which is an “aspect” of the two English tenses.
Before learning about perfect aspects, you should have a firm understanding of how to conjugate verbs in the simple present and the simple past. You should also know how to form negative statements and how to ask questions. It is not neccesary to be be able to use these grammatical structures flawlessly, but they are the first steps to learning English and together they represent what a beginning student should know. Perfect aspects represent a major step in the learning process and place the student at the intermediate level.
Grammatically speaking, "perfect" means "complete," so the perfect aspects indicate the state of completion of an action. Perfect aspects are compound verb forms, composed of at least two verbs, one of which is always the auxiliary verb HAVE. The main verb is in the form of a past participle or present participle.
|present||present perfect||We have studied English.|
|present perfect progressive||We have been studying English.|
|past||past perfect||We had studied English.|
|past perfect progressive||We had been studying English.|