"A house is as big as an elephant."
Translation:Mae tŷ cymaint ag eliffant.
Sympathies, niko_k. Bumping into these sort of things makes me grumpy too. (All together now...) We're still only in Beta.
No I haven't been on Facebook. I'm not holding my breath for all the aggravations to vanish either. I do actually think that, for a free course, Duolingo does very well.
mor fawr is not actually wrong, and it isn't really slang, so it is accepted. There will be situations when people do choose to use it, but in general cymaint is usually better. As yet, Duolingo does not provide a facility for distinguishing between 'correct' and 'hmm, ok in some circumstances...' - although people have asked for it apparently.