at speed

quickly

迅速地

a car flashed past them at speed.

一輛車從他們身邊疾馳而過。

up to speed

Operating at maximum speed.

以合適的速度或標準生產(chǎn)某物或執(zhí)行某事

&I{Informal} Fully informed of or conversant with

【非正式用語】 悉知的，熟悉的

I'm not up to speed on these issues yet.

我對這些事情還不熟悉