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If the suggestions from translation memory or the translation assistants from the tool do not help, you can look for the previously translated string which should be quite similar in our old .po files. You can get these old .po files from here. If still not sure, make it fuzzy. That way it’ll be flagged for us to look at later. You can manually mark a message Fuzzy by inserting !FUZZY! at the beginning of your translation
Some messages are automatically marked fuzzy. More on fuzzy translations: http://translatewiki.net/wiki/FAQ#!!FUZZY!!.
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