in threes
成語所屬單字three
in threes — 慣用語
1. happening or appearing three at a time; in groups of three.
1.慣用語
釋義
接連三個；三個一組
happening or appearing three at a time; in groups of three.
例句
Bad luck often seems to come in threes — first the car broke down, then Ingrid lost her phone, and now the power is out.