I think these are ‘relative clauses’ and there is a little test you can do by seeing if you can fit a who or a which in English - the second half of the sentence would need to go on to explain more…for it to work.
It was The Blues who were the best team in the opening quarter but it was a penalty kick from the foot of Jarod Evans which was the only thing which they had to show for their dominance.
The ‘a’ is invariably not heard in conversation but it causes a mutation which would still appear…
Yes I think it would (a) oedd yn nabod…the present tense being the odd one out having its own word ‘sy’…for which/who…all other tenses using (a) and the word you normally use for that tense.
If you can’t…and ‘that’ fits…it is a subordinate clause (not a relative one) and these have reported speech or thought in the second half…
Eg
I think (that) we are going to lose [thought]
He said (that) his dog was sick. [reported speech]
The present tense uses bod for this - other tenses uses y or yr.
Rich 
Thanks Rich. I will sleep on it and hope it will all make sense in the morning. I think I’ve made some progress in that I can see how to read such a sentence with your guidance. Now it’s a question of noticing when to add them in if I was building such a sentence from scratch!
I believe 100% in “don’t worry about it” advice…these things seem to drop into place in due course…and of course that could be the morning! 
Rich
Our courses don’t match the European Framework exactly, but to give you an idea - by the end of the course you’re able to survive (and enjoy!) a week speaking nothing but Welsh in an immersion situation, i.e. Bwtcamp
A question on pronunciation: I’m a bit unsure as to how the “wy” conbination should sound in some circumstances. For example, how does “dygwyr” differ from “dysgwr”? And how does one pronounce “awyren”? Does “Digwyddiad” sound like “dig-with-iad” or “dig-oi-thiad”?
“Disgwr” would have an ‘oo’ sound, and “disgwyr” would have sort of a “ooee” sound. The two vowel sounds, ‘oo’ and ‘ee’, often blend into each other rather than being two distinct sounds. Makes kind of a subtle difference at times.
In “awyren”, ‘aw’ is the diphthong rather than ‘wy’. So it should be ‘ow-ur-ehn’. Basically ‘hour’ with ‘en’ at the end.
According to Wiktionary, “digwydd” has a ‘wih’ sound. So I assume “digwyddiad” would be the same.
This question just reminded me that I’m not sure what sound ‘wy’ makes in “Gwyddeleg”. Thanks, Wiktionary, for not helping me with that word.
Hi @stephenbranley,
Tricky to give the answer in writing but I’ll give it a go. Wy does vary a bit.
Dysgwyr - sounds like the word for true - gwir.
Awyren - sounds like the word for hour - awr but the r goes with the en - so it’s awy-ren (the r sound links the two)
Digwyddiad - as you’ve put it - dig-with-i-ad, with the difference between dd and th.
Hope that helps
@stephenbranley @AnthonyCusack @meowmocha
Sorry I’m rarely able to understand explanations in English for Welsh sounds, so I can’t understand if the result is the same! 
I’m sure I’ve heard awyren a few times, I believe in an audiobook or song, and I heard it as:
a-wé-ren (with the stress on the e, that’s a bit between an e and an o).
yeah that reads about right
(a-wir-ren, not too r sounds but it blends the two bits)
Here it’s like the English ‘with’ with a g in front - gwith-eh-leg.
What still trips me up is when you get words beginning with gwy- that have a to bach over either the w or the y, like gŵydd (goose) or gwŷr (men - as in ‘Men of Harlech’!).
Also, coming from Monmouth, the river Wye still gets me into arguments - although there are no accents to worry about, there is definitely ‘debate’ as to whether the wy in Gwy (and indeed Trefynwy) is pronounced ooee or oy! To be honest, the wy’s in the middle of words are easier to cope with - there’s not usually as much variance in their pronounciations.
It’s like the tendency to say Myfanwee for Myfanwy. I always end with an “oi” sound.
Whenever I come over the bridge and I’m greeted with the sign for Monmouthshire I have an internal debate about exactly how “Sir Fynwy” is pronounced. “Fun-wee” or “Fun-oy” or somewhere in between?!
I always go for an “oy/oi” sound at the end of words. Doesn’t mean wee is wrong of course.
This is also my preference, but there’s always that nagging doubt!
I’ve always said “Vun-wee”, and I remember the wonderful historian, the late John Davies always said “Vun-oy” - but he never once tried to tell me my pronounciation was wrong (unlike some I’ve come across!), and put it down to dialectual preference
That’s it then. Whatever I pronounce and however I pronounce it, I shall just attribute it to my own dialectual difference!
