He would stay for hours at a stretch in the laboratory.

他能一连几个小时呆在实验室里。

youdao

Whereas purposeful men could make their way across a narrow bridge, the slow diffusion of plant and animals would require an avenue as a continent and available for ages at a stretch.

有目的的人可以通过一座狭窄的桥，而植物和动物的缓慢扩散则需要一条像大陆一样的道路，而且需要很长时间才能使用。

youdao

Today I really swam to my heart's content. I did 3,000 metres at a stretch.

今天我一口气游了三千米，真过瘾。

《新英汉大辞典》

The woman had to travel overseas once a month for three or four exhausting days at a stretch.

FORBES: When You Just Don't Fit In At The Office

Like most nannies, though, the virtual babysitter will work for only eight hours or so at a stretch.

ECONOMIST: For the child who has everything | The

Which is not bad, if you don't mind being cooped up in a boat for weeks at a stretch.

ECONOMIST: The shrimping industry