Ji-Li's aunt- humiliated by Red Guards because she refused to let children pick her mulberry leaves. Aunt Xi-Wen had to paste a da-zi-bao to her front door saying terrible things about her.
The comma would end up between but and orange.
"You may have an apple or an orange, but you can't have both."
This is because you're coming to a conjunction, which usually has a comma preceding, or coming before, it.