prepositions associated with days or time

[Daniellll]

-Do we always use "on" when we are dealing with days:

for example, they might "on" any day during the week?

- what if I am saying" they will pay be both "on or at" the same point in time. should I use on or at?

[rainbkc]

'IN' shows the largest block of time.
e.g. in 100 years, in 2009, in June

'ON' refers to the more specific.
e.g. on Wednesday

'AT' is most specific
e.g. at 8 pm, at that time