Yes, I think you’re sentences are correct.
But also note how the sentence would change if there was no glè very there:
- the work is good: tha an obair math (math unlenited because it is a predicative adjective; it does not directly attribute an obair but complements the verb tha as its predicate)
it is good work:
- tha e na obair mhath literally it is in its good work
- ’s e obair mhath a th’ ann literally good work it is that is in it
notice how here mhath is lenited – as it attributes feminine obair directly – obair mhath good work
Another possibility (but I don’t think used that much in modern language) would be a direct use of copula: is obair (glè) mhath e it is (very) good work.
PS Also, because obair work is feminine, I wondered whether it shouldn’t be
’s i obair… a th’ ann (edit: nope, it’s always ’s e … a th’ ann an …) and tha i na h-obair… – but from searching through the web I think it always uses the masc. pronoun e today and I’ve only found old examples with i of the former, from 19th c. and older and no of the latter. I think in older language it should be ’s i obair (glè) mhath a th’ ann (edit: no, it’s always ’s e … a th’ ann an … in this construction, also historically – verified much later), but still tha e na obair (glè) mhath (as e refers to general it, not to obair).
PPS Funnily Colin B.D. Mark in his Gaelic Verbs: Systemised and Simplified in ch. 10, §A.6., pp. 171–172 in the note ix) claims that Although in all the sentences above the pronoun following the verb agrees in number and gender with the subject of the sentence, the modern tendency is for a neutral pronoun, i.e. e, to be used in all cases where the subject is not a personal pronoun – but he obviously lies speaking about all examples – in the example A.6.4 Is e do shùil do cheannaiche. Your eye is your merchant. the pronoun does not agree in gender with feminine do shùil (it should be is i do shùil…). But this mistake reinforces the use of general e in modern language even further.
And the version is e do shùil do cheannaiche was published in 19th century Gaelic proverbs book, so either the tendency to use e even for feminine is pretty old; or the proverb is even older and e is masculine because it refers to the masculine predicate do cheannaiche and not to the subject (your eye (fem.) is him – your merchant (masc.) – originally those additional pronouns after the copula referred to the predicate).
As always a very thorough and colourful answer. :) Thank you for adding so much interesting reading material about the how and why it's supposed to be written in a certain way as that makes this Gaelic course, which is already very entertaining and interesting, an extremely enjoyable learning experience.
Well, the word actually is an Old Irish borrowing from Latin opus (or rather some other form thereof, probably opera)!
But the connection between the two has been detached for centuries now (and there was never any trace of s in the Gaelic borrowing) – I guess what you’re actually hearing here is the slender /r´/ pronounced as something like [ð̠] which is kinda similar to [z]…
And then Gaelic /b/ isn’t really voiced so it’s rather [p] (as opposed to /p/ which is aspirated [pʰ]), so obair is something like [opɪð̠] which might sound kinda similar to /opus/…