by turns

by turns  {adv. phr.}

Обычным образом один за другим; взаимозаменяя или следуя друг за другом по расписанию.

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.

Син.: IN TURN. Ср.: TAKE TURNS.