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“A couple things” / “a couple of things” in English that I think it is good enough to distinguish the differences.
We will leave in a couple of days.
When using "couple" meaning it is exact. Ex: a lovely couple.
We can use the "for" or "in" preposition before the "couple of hours/times".
This film goes on for a couple of hours.
I'll have it done in a couple of hours.
It will take me a couple of hours to get into London.
What are you doing for the next couple of days?
What are you doing in the next couple of days?