"The boy is tall."
Translation:남자아이는 키가 큽니다.
This new word for boy needs to be introduced. It's not even in the hints.
그 소년(은) is another way of saying "the boy". The answer they have is correct
키 is 'height', but more about size and not, for example, how high a plane is flying. 크다 means 'is big' 키가 크다 would mean 'has big height', a 'you are big' remarking not generam size but tallness
yeah had no idea about the other word for boy, when i tapped the word to get the right translation it didnt even show up there