I'll briefly exercise my pedant muscles to provide some technical terms for general interest: http://en.wikipedia.org/wiki/Uses_of_English_verb_forms#Progressi

I'll briefly exercise my pedant muscles to provide some technical terms for general interest: http://en.wikipedia.org/wiki/Uses_of_English_verb_forms#Progressive http://en.wikipedia.org/wiki/Uses_of_English_verb_forms#Prog... The first bullet is an example of past perfect progressive, which combines the past tense with the perfect and progressive aspects -- in other words, it describes that specific part of an ongoing action (progressive aspect) which has already been (past tense) completed (perfect aspect). The second bullet exemplifies the past perfect, describing an action which has already been completed, without the additional progressive aspect to signify that the action is ongoing. Both are correct, and would likely be understood to mean the same in colloquial usage; the only difference is that the former is somewhat more specific than the latter, in stating that the action is ongoing rather than leaving that to be inferred. http://en.wikipedia.org/wiki/English_verbs#Third_person_singular_present http://en.wikipedia.org/wiki/English_verbs#Third_person_sing... This is a slightly unusual case in English, in that otherwise regular verbs almost always take a trailing (e)s in their third-person singular present-tense form. For example, conjugating to tell in the present tense: 1st person: I tell; we tell 2nd person: you tell; you tell 3rd person: he tells; they tell Presumably this exception exists for historical reasons; why we keep it around, save habit, I have no idea. In any case, we do it with more or less all English verbs, save a few: http://en.wikipedia.org/wiki/English_irregular_verbs#Verbs_with_irregular_present_tenses http://en.wikipedia.org/wiki/English_irregular_verbs#Verbs_w... http://en.wikipedia.org/wiki/English_modal_verbs http://en.wikipedia.org/wiki/English_modal_verbs