Complex sentence: A thermoplastic is made of strong polymers, like bricks, with weak forces holding them together, like mortar; a thermoset is made of strong polymers that bind together and form one molecule, similar to concrete.
Split into simpler sentences: A thermoplastic is made of strong polymers, like bricks, with weak forces holding them together, like mortar. A thermoset is made of strong polymers that bind together and form one molecule, similar to concrete.