"My sister is a model."
अनुवाद:मेरी बहन एक मॉडल है।
You are not typing the word मॉडल correctly. The correct way to type this word is म + ॉ + ड + ल. You are typing म + ा + ॅ + ड + ल which is wrong. If you copy and paste your answer into notepad or word you will see the difference.
Our course should accept your incorrect typing as a typo but currently we are having a few technical problems and I am not sure that it is working properly.