Usage patterns
一度に〈数〉〈物〉all [a number of things] at once
I was troubled when I was asked to do three jobs all at once.
一度に〈事〉を済ませるto get several things done in one go
I got the shopping and my errands done all at once.
一度にたくさんの〈物〉a large number of things all at once
It's hard to carry a lot of luggage all at once.