I am getting this 'pay attention accents' because I am using BOTH accents (I am in Canada and here (in Cape Breton) they have not adopted the elimination of the acute accent, so we prefer to spell "mòr" as "mór". These two words would be pronounced very differently based on the accents. I will continue to use both grave and acute accents based on where I will be using my Gàidhlig, and live with the chastisement from duo.
There are cumbersome ways to do it in windows (not sure how - I'm on a Mac). On a Mac (mine anyway) just hold the key down and a short table of accented letters pops up. Select the number that corresponds to the appropriate accent. On an iPad or iPhone you hold your finger on the letter you want, that little table pops up and you then slide your finger (don't lift or the table will disappear) to the letter with the accent you want.
I believe they were looking for you to type what you heard, not a translation. (at least that's what I got) And there is a 'the' article but there is no 'a/an'. If you want 'a cow' you would just say 'cow'. So although the English says "A cow is big" the direct translation for the same thing from Gàidhlig is "Cow is big"