to be at a loss; to rack one's brains in vain; to think and think but get nowhere; to fail to come up with a good idea
to be at a loss how to continue an offensive; to be frustrated by impregnable defences
to rack one's brains without getting anywhere; to mull over endlessly; to be unable to make up one's mind
to be at a loss; to rack one's brains in vain; to think and think but get nowhere; to fail to come up with a good idea
to be at a loss how to continue an offensive; to be frustrated by impregnable defences
to rack one's brains without getting anywhere; to mull over endlessly; to be unable to make up one's mind