Learn Farsi: بدون این فنرهای کوچک، ساعت کاملاً از کار می‌افتد. - Without these small springs, the watch completely stops working.

I see the verb می‌افتد is singular, but we have the plural فنرهای (springs) earlier in the sentence. Is this an example of an inanimate plural subject taking a singular verb?

Not quite! In this sentence, the subject is actually the singular noun ساعت (watch), which naturally takes the 3rd-person singular verb می‌افتد. However, if فنرها (the springs) were the subject, you would still use the exact same singular verb because of the inanimate plural rule you are learning in this lesson.

How does از کار می‌افتد translate to 'stops working'?

This is a very common compound verb. The infinitive is از کار افتادن, which literally translates to 'to fall from work'. It is the standard idiomatic way to say that a machine, device, or system breaks down or completely stops functioning.

Why is there an ezafe on بدون (without) linking it to the rest of the phrase?

In Farsi, certain prepositions like بدون (without) behave like nouns grammatically and require an ezafe to link them to their object. So when speaking, you must pronounce it as بدونِ (bedun-e) to connect it to این فنرهای کوچک.

Since فنرها (springs) is plural, why isn't the demonstrative word این (these) also plural?

In Farsi, demonstrative words like این (this/these) and آن (that/those) never take a plural marker when they are placed directly before the noun they modify. The plural suffix on فنرها is enough to show there are multiple springs.