一度に + [verb] 一度に + [number/quantity] + [verb] [sentence] (一度に modifies the verb/action in the clause)
Standalone adverbial expression; placed before the verb phrase it modifies.
一度に (いちどに) is an adverbial expression meaning "all at once", "at one time", or "in one go". It indicates that something happens simultaneously or is done together in a single action, rather than being spread out over multiple steps or occasions.
Use 一度に to describe performing an action all together rather than gradually or in parts.
一度に can also describe multiple things occurring at the same time.
It is used to talk about how much can be handled or processed at one time.
一度に often carries the nuance that doing something all at once is noteworthy – either impressive, overwhelming, or inadvisable. It contrasts with doing things 少しずつ (little by little) or 一つずつ (one by one). Compare: