chews over, cogitates, considers, contemplates, debates, deliberates, entertains, eyes, kicks around, meditates, mulls (over), perpends, ponders, pores (over), questions, revolves, ruminates, studies, thinks (about or over), turns, weighs, wrestles (with)

muses (upon), reflects (on or upon), reminiscesanalyzes, explores, reviewsconcludes, reasonssecond-guesses, speculates (about)broods (about or over), dwells (on or upon), fixates (on or upon), frets (about or over), obsesses (about or over)believes, conceives, opinesabsorbs, assimilates, digests, drinks (in)

beats one's brains out (about), cudgels one's brains (about), looks at