Okay, the user wants me to translate "sub-grade" into Italian. Let me think. The term "sub-grade" can have different meanings depending on the context. In construction or engineering, it might refer to the layer beneath the main grade, like the subgrade in road construction. In that case, the Italian term could be "sottofondazione" or "substrato".
Alternatively, if it's used in a different context, like in education or rankings, "sub-grade" might mean a lower grade or a subsidiary grade. Then, the translation might be "sottograduato" or "sottogruppo". But I need to check if there's a standard translation for this term.
I should also consider if the user provided any context previously. Looking back, the user's initial message was just "sub-grade" with no additional info. Since there's no context, the safest approach is to use the most common translation. In civil engineering, "sub-grade" is often translated as "sottofondazione". However, I should verify if "sottofondazione" is the correct term in Italian technical jargon.
Another possibility is "sottosuolo", which refers to the ground beneath the surface. But that might be more about the subsoil rather than a grade. Let me check some references. In road construction, "subgrade" is indeed "sottofondazione" in Italian. So, "sub-grade" would be "sottofondazione".
Alternatively, if it's a typo or a variant spelling, maybe "sub-grade" is meant to be "subgrade", which would still translate to "sottofondazione". Since the user wrote "sub-grade" with a hyphen, but in Italian, the term without the hyphen is used. So the translation should be "sottofondazione".