Python 2,  126 120  112 bytes

-8 bytes thanks to Anders Kaseorg _{(I thought I'd migrated this from Python 3, but turns out I'd forgotten!)}

A port of my Jelly answer works well in Python too...

for w in"agar abreacts acknowledges codeterminations deindustrializations".split():print w[2:-1],w[2:],w[:-1],w,

Try it online!

Prints:

a ar aga agar react reacts abreact abreacts knowledge knowledges acknowledge acknowledges determination determinations codetermination codeterminations industrialization industrializations deindustrialization deindustrializations