*imperfect, imperfect tense, progressive, progressive tense

*tense -a grammatical category of verbs used to express distinctions of time

*present progressive, present progressive tense -a tense used to express action that is on-going at the time of utterance

*past progressive, past progressive tense -a progressive tense used to describe on-going action in the past; "`I had been running' is an example of the past progressive"

*future progressive, future progressive tense -a progressive tense used to express action that will be on-going in the future; "`I will be running' is an example of the future progressive".