concentrate verb

ADV. fiercely, hard, intently She was sitting at her desk concentrating hard. | fully, properly | mainly, predominantly, primarily | particularly | entirely, exclusively, purely, solely

VERB + CONCENTRATE be unable to, can't, couldn't I tried to work but I found I couldn't concentrate. | be difficult to, be hard to, be impossible to | tend to UK banks tend to concentrate on short-term lending. | try to

PREP. on/upon He concentrated mainly on the flying and spoke very little.