"She is not a child."
Translation:Cô ấy không phải là một đứa trẻ.
I'm struggling with diacritics. This is my answer: "cô ấy không phải là một con trè." but it mentions the words "ấy", "phải", "một", "con" and "trè" as wrong. True, con should be đữa, but I don't understand why all the others are marked as wrong. It seems duolingo doesn't seem to recognize the diacritics. Does anyone experience this too?
It has to do with character encoding. The letters with vietnamese diacritics can be encoded in different ways by softwares, and some softwares use different encodings in different situations (for example my tablet switches encoding when using auto-complete, this một is in fact different from this một). Duolingo seems to prefer a particular encoding over the others, however thankfully it only gives a warning if the answer differs only in encoding from the correct one.