could someone show my why is this "after I WENT on the bus" instead of "after I GET on the bus"? I don't know how you can tell which tense to use from this sentence.
These i-dot patterns are tenseless - the tense can only be inferred from the context:
- Ar ôl i fi fynd ar y bws i Lanidloes, roeddwn i wedi cael cinio ac wedyn mynd adref - After I had gone on the bus to Llanidloes, I had had lunch and then gone home.
- Ar ôl i fi gael cinio, es i adref - After I had had lunch I went home.
- Ar ôl i fi fynd ar y bws i'r Fenni, bydda i'n dal y trên i Amwythig - After I go (or 'have gone') on the bus to Abergavenny, I'll catch the train to Shrewsbury.
(To save confusion, it is common to call the letter i, 'î-dot' and the letter u, 'û-pedol' or 'û-cwpan' as they can sound the same or similar in some dialects.)