Okay, the user sent "sub-grade". Let me check the translation rules again. The first rule says to translate all content into Portuguese. The second rule states that if the content is already in Portuguese, leave it unchanged. The third rule is to provide only the translation result without explanations.
So, "sub-grade" is in English. I need to translate it into Portuguese. The direct translation would be "sub-grade" as well, but maybe in Portuguese it's "sub-grau" or "sub-classificação". Wait, "sub-grade" could refer to a sub-level or a lower grade. Let me confirm. In Portuguese, "sub-grade" might not have a direct equivalent, but sometimes technical terms are kept as is. Alternatively, "sub-grau" could be used, but I'm not sure. Maybe the user wants the term kept as "sub-grade" since it's a technical term. However, according to the rules, I need to translate it. Let me check a dictionary. Hmm, "sub-grade" isn't a standard Portuguese word. Maybe the correct translation is "sub-classificação" or "sub-nível". But without more context, it's hard to tell. The safest approach is to translate it as "sub-grau" or "sub-classificação". Wait, the user might be referring to a specific term in a certain field. Since I don't have context, I'll go with the direct translation. Alternatively, maybe "sub-grade" is already a Portuguese term. Let me check again. No, in Portuguese, "sub-grade" isn't commonly used. The correct term might be "sub-nível" or "sub-classe". But since the user wants the translation, I should provide the best possible equivalent. I think "sub-nível" is more appropriate here. So the translation would be "sub-nível".