Se la seruro denove ne funkcios, ni petos tiun laboristinon ŝanĝi ĝin morgaŭ.

If the lock does not work again, we will ask that worker to change it tomorrow.

Breakdown of Se la seruro denove ne funkcios, ni petos tiun laboristinon ŝanĝi ĝin morgaŭ.

• ni: we
• morgaŭ: tomorrow
• se: if
• ne: not

Questions & Answers about Se la seruro denove ne funkcios, ni petos tiun laboristinon ŝanĝi ĝin morgaŭ.

Why is it funkcios after se? In English we usually say if the lock doesn’t work again, not if the lock will not work again.

Esperanto does not follow the English rule that an if-clause normally uses present tense for future meaning. After se, Esperanto can use the tense that matches the time actually meant.

So here:

• Se la seruro denove ne funkcios = if the lock does not work again / if the lock will fail again

Because the possible problem is in the future, funkcios is completely natural.

Why not use -us instead, like Se la seruro denove ne funkcius, ni petus...?

-os and -us give different shades of meaning.

• -os = a real future possibility
• -us = a more hypothetical or less direct situation

So:

• Se ... ne funkcios, ni petos ... = If it fails again, we will ask ...
• Se ... ne funkcius, ni petus ... = If it were to fail / if it didn’t work, we would ask ...

The sentence as given sounds like a normal plan for a possible future event, so -os fits best.

What does denove mean, and why is it placed there?

Denove means again.

In this sentence it goes with ne funkcios, so the idea is:

• if the lock doesn’t work again
• if the lock fails again

Its position is natural because it sits close to the verb phrase it modifies. Esperanto adverbs are fairly flexible, but this placement is clear and normal.