A good translator does not translate words and phrases, rather he conveys thoughts and ideas behind the phrase in the target language taking into consideration the context in which the sentence is written.
If the context is not provided or not available, then the translator has the freedom to translate the sentence that would be best understood in the target language.
"I didn't eat your sandwich" - If this phrase is a part of a conversation or a story, the translator will take into context the entire conversation while translating.
"I didn't eat your sandwich" - If this is just a slogan, punch line or a tag line with no context whatsoever, the translator will translate it the best way in which it can be understood in the target language.