English has four "progressive" verb forms, each of which is an "aspect" of the two English tenses.
Progressive aspects are used to describe actions that happen over an extended period of time. This time period may be short or long and take place in the present, past, or future. Progressive aspects are compound verb forms, composed of at least two verbs, one of which is always the auxiliary verb BE. The main verb is in the form of the present participle.
|present||present progressive||We are studying English.|
|present perfect progressive||We have been studying English.|
|past||past progressive||We were studying English.|
|past perfect progressive||We had been studying English.|
Special note: Except for French, all Romance languages have a progressive form. For speakers of these languages, the concept of the progressive will be easy to comprehend. Many other languages, however, do not employ progressive aspects so this grammatical concept may be more difficult.