Bess'. We often add 's to everything in speech, but I learned that to show possession, only an apostrophe goes at the end of a proper name ending in S.

They're synonyms, but we don't use the word "discover" very often except in academia.

He seems like you.

*you'll. To make do with something means it will have to be sufficient (even though it's not). So, if you have a small house but wanted a bigger one, you'll have to adapt and make it be enough for you...it'll have to make do. ;) You can also just say "It'll have to do." to achieve the same meaning (in this case). Hope this helps! Best, ~Maidhc

Laws or rules of science....Planets revolve around a star. An observation of that would lead to a law of reason (scientific reason, in this case) being made about it. For example, Einstein's equation of E=MC².

I would caution you against translating sibh as "you guys"; that...rather recent "phenomenon"...is unique to English, and is best avoided so as to not cause confusion or offense; Just say "you". People can figure out the meaning from context. I mean, people can still do that in English, too, but, people's attention spans have shrunk to a microscopic level. :-/ But that's another conversation. :-)

Sin é an gasúr nach léann leabhair. This is the boy who doesn't read books. (I prefer the word buachaill, as gasúr is normally reserved for a boy of rather young age; you'll sometimes see it translated to "little boy". Same goes for girseach vs. cailín, the latter being the more common due to age-relevance). Hmm, for the last one: "Sin é an cailín nach léann a athair leabhair. This is the girl whose father doesn't read books." I would say that should be "a h-athair", because even though "calín" is a masculine noun, the person is not, so you would follow the possessive rules: mo + H do + H a + H a - nothing, except +H for nouns beginning with a vowel ár - eclipsis bhur - eclipsis a - eclipsis

It can be used in either way, but it's usually used informally. Informally, it's an expression to indicate a long period of time (real or perceived). Formally, it really IS talking about very long lengths of time (The Bronze Age, the Iron Age, etc).