on

We do sometimes omit on in time expressions in informal English, although I think it is more characteristic of American English than British English. So in your first example, Anid, both versions are possible. Compare the following:

• They will meet on Sunday next week.
• They will meet Sunday next week.

• Our wedding anniversary is the 22nd of October.
• Our wedding anniversary is on the 22nd of October.

• We’re going to have a game of tennis Wednesday evening.
• We’re going to have a game of tennis on Wednesday evening.

Note that if we say: I’ll see you next Sunday week rather than I’ll see you Sunday next week, it is not the following Sunday that is intended, but the one after that!

For your example of a time expression with the past tense, I think we would normally use one of the following formulations:

• It happened last Friday.
• It happened on Friday.

'next' and 'last'

Note the pitfalls when using next and last. We rarely use prepositions with time expressions involving next and last And there is a big difference in meaning and use between next and the next and last and the last. Compare the following:

• I shall be working for the next week and then I shall be on holiday. ( = starting now for the next five or seven days)
• I shall do some work next week before I go on holiday. ( = some work, but not every day)
• I’m going to have driving lessons next year. ( = at some point during the year)
• For the next twelve months I shall be in Birmingham on a post-graduate course. ( = all 12 months, starting now)
• The last year has been hell! First the divorce, then I lost my job! ( = all 12 months up till now)
• I got divorced last year and I plan to remarry this year. ( = at some point during the year)
• I’ve had diarrhea for the last week, doctor. Can you give me something for it?
• I had diarrhea last week. Couldn’t eat anything for three days.

Note prepositional use and the use of the present perfect and past simple tenses in the above examples.

'this' or 'next'?

Finally, we sometimes need to clarify which date we are referring to if it is in the immediate future by using on or this instead of next. Compare the following:

• Let me see. It’s Wednesday now so I’ll give you a ring next Friday.
• ~ Do you mean this coming Friday or the following one?
• ~ No, no, this coming Friday. I’ll ring you this Friday. I’ll phone you on Friday.