Bod cannot be followed by a conjugated verb, only by the verbnoun.The best way for you to translate your example, Hazel is by saying:Gwn dy fod wedi mynd i Sbaen llyneddRwy'n gwybod dy fod wedi mynd i Sbaen llyneddOften, you will just have to accept that subordinate clauses generally do not have a tense and that you will realise whether it is the past or present by the tense of the main clause a