Can we translate “part” into number to interpret “for the most part” as “most of us”? In other words, we as a whole is a whole pie and those who have been here for less than 60 years constitute only a part of the pie. If this works, then students understand the sentence better. The phrase can be translated into “in general” too, but that doesn’t help understanding.
OK. If the above works, can we use the same method to explain “part” in the following “There's also a part of me that feels indignant on behalf of my Caribbean slave ancestors”. I can hardly translate “part” here into a physical part of the body. Any suggestions?