I can only carry two at a time.

我一次只能带两个。

《牛津词典》

She ran up the stairs two at a time.

她一步两阶地跑上楼梯。

《牛津词典》

When I was doing the latter two tasks for an hour or two at a time, the battery ran down so slowly for me that I stopped thinking about it.

我执行后两种任务、一次执行一两个小时的时候，电池损耗实在太慢，我都不去想它了。

youdao

Brown's men joined him, one or two at a time, over the next several months.

VOA: special.2009.06.18

First of all, it will only be a minute or two at a time, maybe once or twice a lecture.

首先，每次只有一两分钟，一堂课最多不超过两次。

哈佛公开课 - 幸福课课程节选

And you like working with kids. But maybe just one or two at a time.

你挺喜欢跟小孩子相处的，但也仅仅是同时跟一两个孩子打交道的时候。

How many课堂 - SpeakingMax英语口语达人

X-rays seem to flare up for a month or two at a time, and then subside.

ECONOMIST: The dizziest, giddiest stars

Scott Anixter picks up companies the way Casanova once collected women -- sometimes two at a time.

FORBES: All in the family

Working with two at a time, I twisted the ropes of dough together and tucked them into baking tins.

WSJ: Delicious Babka With Nutella