Timeline in linguistics: past point or period in time.
The Past
We need to ask 1question to determine if an action was in the past:
Action / state:
Is the action / state happening now or at a period of time which is still going on? (today, this year) – no
Let’s determine what is period of time which is still going on.
Every day – meaning that tomorrow will be included in the every day chain.
He drinks 5 cups of water every day
He drinks every day and tomorrow he will do it too, because he does it every day. The synonyms in this sense can be sometimes, from time to time, usually, often etc. Anything that shows a recurring basis including next time from the moment of speaking.
Now compare every day EXcluding tomorrow:
He drank 5 cups of water every day
He drank this much water every day in the past and tomorrow you don’t know what he is going to do. The same happens to sometimes, from time to time, usually, often etc. Anything that shows a recurring basis, just like every day, but EXcluding next time from the moment of speaking.
Sometimes, he drank 5 cups of water
In this example we don’t know if next time from the moment of speaking will be included.
To summarize, when we know that next time, in the series of recurring times of actions / states, will continue into this sequence from the moment we are speaking this sentence, then we can consider such period of time as “still going on.”
Alright, let us return to our question:
He drinks 5 cups of water every day
Is the action / state happening now or at a period of time which is still going on?
The answer is yes. So. it’s not a past tense.
Another example:
He drank 5 cups of water every day
Is the action / state happening now or at a period of time which is still going on?
Yes. So it’s a past tense.
He is drinking water now.
Is the action / state happening now or at a period of time which is still going on?
Yes. He is drinking water now. So it’s not a past tense.
He was drinking water at that time.
Is the action / state happening now or at a period of time which is still going on?
No. So we must use a past tense.
Interestingly, the present is always dynamic, it is constantly moving together with the current point in time, with every micro second of it. Past is “before now, before current time” or “before present,” and future is always “after now, after present, after current time.” Past and Future are static, they are statically fixed: at 5 tomorrow, from 5 to 6 yesterday etc.
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