"Ddoe, dw i wedi yfed coffi."

Translation: Yesterday, I have drunk coffee.

[Sir_Percival]

English 'drank' is correct here.

[Zismac]

Surely "had" would be more appropriate?

[ibisc]

Thanks for pointing out the awkward English. This default translation has now been changed to 'Yesterday, I drank coffee'.

('I had drunk...' would actually require a different tense in Welsh, the pluperfect - ro'n i wedi yfed....)

[Dim-ond-dysgwr]

The Welsh too is awkward in my view. Should be "Ddoe yfes i goffi" since yesterday is over and done with. If want you really want is (as I suspect) to test the construction "I have drunk" then you should really choose a sentence like "Dwi wedi yfed coffi heno" (I've drunk coffee tonight), which makes sense since tonight is still ongoing.

[ijtro]

Did put in that response, but it still marks me as wrong.