Divide the following words into three groups, those which are used in Indefinite (Simple); Continuous (Progressive); Perfect : Always, now, two weeks ago, ever, never, since, yet, often, already, usually, at present, recently, generally, in a week, from 5 till 6 o’clock tomorrow, all morning yesterday, last Monday, by Monday, in 1989, every day, yesterday, just, all the year round, lately, sometimes, in the future, last year, on the 8th of March 1998, the day after tomorrow, this winter, next week, as a rule, since summer, tomorrow, just now, seldom, all day long, rarely, a week ago, three days ago, throughout the year.