"Ligim é dul."
Translation:I let it go.
Because "I am letting" is continuous present. "I let" is usual present: not only do I let it go now, but I usually let it go. I am not only letting it go this present time. I am a let go type of gal.
In Irish the difference is stronger than in English: you might say in English "I am eating porridge every morning", and some may find it inaccurate. In Irish it would just make no sense to say "Taim ag ithe leitean gach maidin"
Which is a third way, without direct equivalent in English, thus the "I do be eating... every morning" used to render it in English.
One more reason to maintain a strong distinction between these 3 forms and their English equivalent.
The point of this exercise is that here the Irish is not using a continuous form, thus it would be inaccurate to use a continuous form in English.