Learn Hardcore Swahili: Magari yanapita chini ya daraja la juu kila asubuhi. - Cars pass under the overpass every morning.

Swahili verbs carry a subject-marker prefix. Magari belongs to noun class 6, whose subject marker is ya-. You then add the present/aspect marker -na- plus the verb stem -pita (“pass”). So:
ya- + na- + pita → yanapita (“they are passing” / “they pass”).

What’s the difference between yanapita and hupita?

Both can express habitual or ongoing action:
• -na- is the simple present (continuous or habitual).
• hu- is sometimes called the “habitual” marker.
In practice yanapita is more common for “they pass”/“they are passing,” while yahupita would stress “they usually pass,” but many speakers simply use yanapita in both senses.

Why is it chini ya daraja and not just chini daraja?

Chini functions like a preposition “under,” but to link it with its noun you insert the genitive/linking marker ya. So chini ya daraja literally means “under of bridge,” i.e. “under the bridge.”

In daraja la juu, why is the linker la instead of ya?

Daraja (“bridge”) is singular class 5, whose genitive/linking prefix is la-. Therefore you say daraja la juu (“bridge of high”), which we interpret as “high bridge” or “overpass.”

Why doesn’t juu change form to agree with daraja?

Juu is a locative/adverb meaning “high” or “above.” It doesn’t take noun-class prefixes itself—only the linking morpheme (la- here) agrees. Juu remains unchanged.

What does kila asubuhi mean, and why doesn’t asubuhi take a prefix?

Kila means “each” or “every” and is invariable (it does not agree with noun classes). Asubuhi therefore stays in its base form. Together kila asubuhi = “every morning.”

Could you make this sentence future tense instead?

Yes. Replace the present marker -na- with the future marker -ta- (keeping the same subject marker ya- for class 6):
Magari ya-ta-pita chini ya daraja la juu kila asubuhi.
That is, Magari yatapita chini ya daraja la juu kila asubuhi = “The cars will pass under the overpass every morning.”