Английский словарь американских идиом - fill in

{v.} 1. To write words needed in blanks; put in; fill. * /You should fill in all the blanks on an application for a job./ 2. {informal} To tell what you should know. * /The new boy didn't know the rules so Bob filled him in./ * /The teacher filled in Mary about class work done while she was sick./ 3. To take another's place; substitute. * /The teacher was sick and Miss Jones filled in for her./