Breakdown of ما چرخدندهها را روغنکاری میکنیم تا اصطکاک کم بشود.
ما
we
راrâ
definite direct object marker
تاtâ
so that
شدنshodan
to become
Questions & Answers about ما چرخدندهها را روغنکاری میکنیم تا اصطکاک کم بشود.
The current lesson is about inanimate plural subjects taking 3rd-person singular verbs. Does that rule apply to چرخدندهها in this sentence?
No, because چرخدندهها (the gears) is the direct object here, not the subject. You can tell because it is followed by the object marker را. The subject of the first clause is ما (we), so the verb روغنکاری میکنیم matches it. The rule you are learning only applies when inanimate plurals are the doer of the action!
Why do we use the subjunctive form بشود instead of the regular present tense میشود at the end?
The word تا here means "so that" or "in order to." Because it introduces a desired outcome or goal rather than a guaranteed fact, it forces the verb in that clause into the subjunctive mood. That is why میشود changes to the subjunctive بشود.
Since بشود comes from شدن (to become), can the بـ prefix be dropped here?
Yes! With the verb شدن, the subjunctive بـ prefix is completely optional. You will very often see or hear this exact sentence end simply with کم شود, which means the exact same thing.
What are the smaller root words used to build چرخدندهها and روغنکاری?
چرخدنده combines چرخ (wheel) and دنده (tooth/rib/gear), with ها at the end to make it plural. combines (oil) and (working). So the sentence literally translates to doing "oil-work" on the "tooth-wheels".