rack ones brains (verb) concentrate: think about closely
Sinonime: apply,
attend, be engrossed in, bring to bear, brood over,
center, consider closely,
contemplate, crack one's brains, direct attention,
establish,
examine, fix attention, fixate,
focus, focus attention, get on the beam, give attention, hammer away at,
hammer*, head trip,
intensify, knuckle down,
meditate,
muse,
need, occupy thoughts,
peruse,
ponder, pour it on,
put, put mind to, rack one's brains, rivet,
ruminate,
scrutinize,
set,
settle,
study,
sweat, think hard, weigh