That's because only the interpretations that Duolingo marks as correct are a valid translation. Any other interpretations that you may be able to see (or write) for this phrase are wrong.
Languages are not a simple matter of this word here always equals that word there. If it were, we would already have babelfish-style translating machines that could instantly understand another language perfectly for you. Part of learning a new language is learning how to correctly interpret each phrase, including what things are idiomatic and what things can be deduced by knowing some basic grammar rules.