Several double prepositions in Irish are followed by the genitive or possessive. An example that you have already seen in these lessons is os cionn, meaning above. Os cionn an bhoird (ohs kyuhn uh VWIRD) means "above the table".
Three others are:
go ceann (goh KYOUN); to the end of or for the duration of. Examples:
go ceann na cuairte (nuh KOO-ahrt-ye), for the duration of the visit; go ceann na míosa (MEES-uh) seo, to the end of this month; go ceann an chogaidh (K*UHG-ee), for the duration of the war.
It can also mean "to the top of", as in : go ceann an chnoic, to the top of the hill.
i gceann (i GYOUN), at the end of (one meaning). For example: i gceann coicíse (KEYE-kee-shuh), at the end of a fortnight, in two weeks' time. i gcionn (i GYUN) means this also.
ar feadh (er fa), during or along. An example: ar feadh an bhóthair is "along the road".
Sentences: Beidh méann go ceann míosa, I will be there for a month.
Beidh mésa bhaile i gceann míosa, I will be home at the end of a month.
Chonaic méNóra ar feadh an lae sin, I saw Nora during that day.
Fuair mémo lón ar feadh na sráide sin, I got my lunch along that street.