本を読みながら、私は眠ってしまった。

book; volume; script; this; present; main; head; real; regular; counter for long cylindrical things; counter for films, TV shows, etc.; counter for goals, home runs, etc.; counter for telephone calls

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to read; to count; to guess; to predict; to read (someone's thoughts); to see (e.g. into someone's heart); to divine

while; during; as; while; although; though; despite; in spite of; notwithstanding; all; both; as (e.g. "as always", "as long ago"); in (e.g. "in tears")

I; me; private affairs; personal matter; secrecy; selfishness

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

to sleep (not necessarily lying down); to die; to close one's eyes