Re: No conjugation?
You've got great replies from reineblanc and Superhero1, so this is just for additional explanation related to your sentence for reference.
Originally Posted by alodia
Another possible translation is "I arrived home late after 11 at night because the gig finished late."
'끝나' in your sentence has - 아10「2」까닭이나 근거 따위를 나타내는 연결 어미.
The reason why you can't see ending -아 is 한글맞춤법.
Article 34 of section 5, chapter 4: It is written as the shortened form if '-아/-어, -았-/-었-' combines with vowel 'ㅏ, ㅓ'.
e.g 가아 >가, 나아> 나, 가았다>갔다
-고, -아, -서 are conjunction-endings that attach to verb or adjective stems. The conjunction 그리고, 그래서 don't attach to stems.
I don't see any difference if '나' is changed to '나서' in meaning, but it seems clumsy because of the repeated '-서', 끝나서 and 넘어서.
(The reason why it clumsy is since we avoid using same endings, josas if possible.) But, there's some difference if you use '끝나고' conjunction-ending '-고' relates '공연이~고' clause and '밤~도착했다' clause.
공연이 늦게 끝나 밤 열한 시가 넘어서 집에 도착했다. (fine)
공연이 늦게 끝나고 밤 열한 시가 넘어서 집에 도착했다.(fine but different from two)
공연이 늦게 끝나서 밤 열한 시가 넘어서 집에 도착했다.(no error but a bit clumsy)
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