first come first served
先到先得，按順序依次服務
口語·書面·表示先到先得
英文釋義
the principle or practice of allocating resources or benefits based on the order in which they are requested or obtained
例句
The free tickets are limited, so it's first come first served at the box office.
典故來源
源自商業和服務業，最早到達的顧客最早得到服務，強調按到達順序分配資源。