Translation:The school is opposite the restaurant.
This exercise came with the words to choose, but the right English preposition ("opposite" or "across from") wasn't listed. The only prepositions available were "around" and "before". I guessed "The school is around the restaurant" and got it marked wrong, with "The school is before the restaurant" given as correct... but neither of those is correct, is it? Can "os comhair" really mean that? (I reported this as a problem; hope I wasn't wrong to do so.)
Means "over" or past x/y. The table at the bottom of this page as 3 other compound prepositions having to do with "os". http://www.nualeargais.ie/gnag/genpraep.htm#abgeleitet
1). The 2nd declension has not only nouns ending slender, but also those ending with eog, óg, or lann (incl. bialann). (http://nualeargais.ie/foghlaim/nouns.php?teanga=)
2). Nouns in the 2nd declension are usually f.
Normally, m. nouns end broad (a, o, u). Exceptionally, bialann and leabharlann are f. (teanglann.ie). Are all words ending in lann f.?
3). *Are words ending in eog and óg also all (exceptionally) f.?
4). Is there a list of m. words in the 2nd declension?/ A rule explaining why they are there? nualeargais.ie mentions im, as well as sliabh. Wiktionary also lists teach.
Plural nouns are eclipsed after the plural definite article na in the genitive.
The singular definite article for genitive feminine nouns is na, and bialann is a feminine noun.
Singular feminine nouns are not eclipsed after the singular definite article na in the genitive.