Английский словарь американских идиом - by turns

{adv. phr.} First one and then another in a regular way; one substituting for or following another according to a repeated plan. * /On the drive to Chicago, the three men took the wheel by turns./ * /The teachers were on duty by turns./ * /When John had a fever, he felt cold and hot by turns./ Syn.: IN TURN. Compare: TAKE TURNS.