Thus, it seems I should study how such structures work and thereby learn whole families of 4-character expressions at a time.
Question: What are the repeatedly used structures in 4-character expressions (e.g. chengyu) and what do they mean?
I'm seeking a kind of overview of major structures (those that occur in multiple 4-character expressions, like
x而y之 above) for 4-character expressions, and a brief explanation as to how to interpret them. It looks like
x而y之 is an adjective that combines
x而y之 is just one example, and there are others like
千x万y (see also Chengyu with two numbers).