Hi all,

I'm trying to keep all the verb tenses straight, but some of them seem to overlap in usage. For example,

"They were stretching when the arena alarms went off."
"They had been stretching when the arena alarms went off."

So I've been working on a logical system to give some guidance. These are not hard and fast rules, but seem to be true so far in my practice. Some tenses are missing, and that's because of my earlier thoughts that some to be very close in definition.

o To express one event in the present and one event in the past, use simple present and simple past.
o To express one event in the past and one event earlier in the past, use simple past and past perfect.
o To express one event in present and one event in future, use simple present and simple future.
o To express two events in the past at the same time, use simple past for both.
o To express two events at the same time in the present, use simple present for both.
o To express a repeating event in future, use progressive future.
o To express an action or event that repeated in the past, use progressive past.
o To express an action that started in the past, and continues into the present, and no information is given on if it will continue into the future, use present perfect.
o To express an action that started in the past, continues into the present, and may continue into the future, use present perfect progressive.
o To express an event that will occur in the future before another event, use future perfect.

Any feedback on this, or in general keeping the 12 tenses straight, is appreciated .