-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?
'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