Er.... excuse me, true friend, do you know the language varies throughout the country? You should be aware before starting to point out someone as wrong. At least in my city, the capital of Brazil, Largo / Amplo / Grande are essentially adjectives to express a relatively great size, quantity, extent, etc.. These words are very close in meaning. Being 'Largo' more related to 'width', 'Amplo' to space & 'Grande' to the overall size of something. Those sentences i gave are preferable to be used with 'grande' but there is no problem in saying 'largo', here where i live.
thank you for your insight. This is what makes duolingo a great tool. we can join comments from a variety of regions. I commented that cause since I was a kid I had to remeber: Dont confuse large and largo... it means grande... I think I was just too enphatic on that. Sorry for my lack of knowledge. i really had never heard of the expressions you mentioned, but that actually doesnt mean it is wrong...
I use largo for "loose" when we have this verb conjugated for "I" in the 1st singular person in the simple present tense. "I loose the sword" = "eu largo a espada". to loose = largar, soltar. It's only a coincidence in this conjugation, but largo is also an adjective meaning "wide" (variation in gender and number for the adjetive largo: larga, largos, largas)