Key words for English tenses

1. Perfect Continuous

1.1. for an hour, for a week, for a long time, for five years, for years,  in years,  all day, all morning, since, how long

2. Perfect

2.1. just, already, yet, ever, never, once, twice, several times, always, by now, up to now; so far, before, for an hour, for a week, for a long time, for five years, for years, in years, since, lately, recently

3. Continuous

3.1. now, at the moment, currently, this month, this year, tomorrow

4. Simple

4.1. every day, usually, always, sometimes, rarely

5. Past

5.1. Simple

5.1.1. yesterday, ago, 2 weeks ago, last week, a long time ago

5.2. Continuous

5.2.1. while, when, at 5 o’clock yesterday

5.3. Perfect

5.3.1. by the time, before,  after,  when (in the meanings "by the time; after"), before last week,  by two o'clock yesterday.

5.4. Perfect Continuous

5.4.1. for, since, how long, before, after

6. Present

7. Future

7.1. Simple

7.1.1. tomorrow, next week, soon

7.2. Continuous

7.2.1. at this time tomorrow

7.3. Perfect

7.3.1. by the end of this year, by this time tomorrow, in two years time, in July next year, in another five months

7.4. Perfect Continuous

7.4.1. for, by the time