Por poco pierdo el autobús de las ocho, pero la conductora esperó unos segundos.

I almost missed the eight o’clock bus, but the driver waited a few seconds.

Breakdown of Por poco pierdo el autobús de las ocho, pero la conductora esperó unos segundos.

• yo: I
• pero: but
• de: of
• las: the

Questions & Answers about Por poco pierdo el autobús de las ocho, pero la conductora esperó unos segundos.

What does por poco mean here, and how is it different from casi?

Here por poco means almost or very nearly.

So:

• Por poco pierdo el autobús = I almost missed the bus

You could also say Casi pierdo el autobús, and the meaning is basically the same.

A useful nuance:

• casi is the most neutral, everyday word for almost
• por poco often feels a bit more vivid or dramatic, especially when something bad or inconvenient nearly happened

So por poco works very well here because missing the bus would have been a problem.

Why is it pierdo and not perdí, if the sentence is about the past?