If I've said it once, I've said it a hundred times.

　　這事我曾經(jīng)說(shuō)過(guò)，而且是說(shuō)過(guò)很多次了。

　　An opportunity like this comes once in a lifetime.

　　像這樣的機(jī)會(huì)一生也許只會(huì)遇到一次。

　　It made a refreshing change to be taken seriously for once.

　　總算有一次受到認(rèn)真對(duì)待，這變化真是令人耳目一新。

　　He was once the great white hope of British boxing.

　　他一度曾是英國(guó)拳擊的希望所在。

　　We need to settle this once and for all.

　　我們需要把這事一次解決。