"How were the lessons?"
Translation:Sut roedd y gwersi?
Strictly speaking there is no need for a mutation after 'Sut' , however 'Sut oedd' is widely used even in the Welsh for adults course we support, so in actual fact there is no difference, either is accepted.
Thanks, good to know that both are equivalent in this context.
I'm a bit confused by your reference to a mutation, though - the difference between "oedd" and "roedd" isn't one of the standard mutations, is it?
Sorry that was me confusing myself. You're completely right it's nothing to do with mutations. It's about which form of the verb comes after the interrogative, statement or question.
eg after 'beth and pryd'
Beth oedd yn y cwpan? What was in the cup?
Pryd oedd y ffilm? When was the film?
Both of these use the question form of 'roedd' ir oedd.
But 'Sut' as a rule doesn't. This is noticed most notably with weather.
Sut mae'r tywydd? = How is the weather?
Sut roedd y tywydd? = How was the weather?
Sut bydd y tywydd? = How will the weather be?
In the past tense, sut oedd, is often used instead even though it's not strictly correct.