"Our relatives eat at the wedding."
Translation:Itheann ár ngaolta ag an bpósadh.
gaolta means "relatives". After plural possessive adjectives (our, your, their), you eclipse the noun - ngaolta. After singular possessive adjectives (my, your, his) you lenite - ghaolta. (The exception is "her" which doesn't eclipse or lenite).
The difference is most helpful for a, which can mean "his" (a ghaolta - "his relatives"), "her" (a gaolta - "her relatives") or "their" (a ngaolta).
As in English, both terms are widely used in the vernacular for terms associated with the actual event (both languages have lost the distinction between the specific event and the associated celebration, for the most part):
comóradh diamaint pósta - "Diamond wedding anniversary"
bainis eaglaise "A church wedding" but you also have "some people prefer a church wedding" - is fearr le daoine áirithe pósadh san eaglais
fáinne pósta - "a wedding ring"
gúna pósta - "a wedding dress"
cáca bainise - "a wedding cake"
bainis bhán - "a white wedding"
lá do phósta, lá do bhainise - "your wedding day"
nuaphósta - "newlywed"
For terms associated with "marriage", such as "marriage guidance" or "married name", pósta is used.
Pósadh is both the state of marriage and the ceremony:
You can make the case that the ceremony takes place at the church or registry office, and people only eat at the bainis, not at the pósadh, but it's a distinction that not everyone will agree with.
And while you're on about réamhfhocail, there's the issue of whether it should be ag or ar.
The only thing that is actually labelled a "quiz" that I know of in Duolingo is the Progress Quiz - the whole point of which is to figure out how much progress you have made. It does that by asking questions from the whole course - the point at which you can't respond correctly indicates your progress. If the "Progress Quiz" was tailored so that someone who had only done the first 5 or 6 skills could answer all the questions, it wouldn't be measuring your progress.