Asilimia kubwa ya wanafunzi walifaulu mtihani wa leo.

In Swahili, adjectives usually come after the noun they describe.

So:

• asilimia kubwa = a large percentage
• literally: percentage large

That word order is normal in Swahili:

• mtoto mdogo = small child
• nyumba kubwa = big house

So asilimia kubwa follows the usual noun + adjective pattern.

Here ya means of.

So asilimia kubwa ya wanafunzi means:

• a large percentage of the students

This is a linking word often called the genitive connector or possessive connector. It connects one noun phrase to another.

In this sentence:

• asilimia kubwa = large percentage
• ya wanafunzi = of the students

So ya is the word that links those two parts.

The connector changes according to the noun class of the noun that comes before it.

Here, the word before the connector is asilimia, and it takes the connector ya.

Compare:

• kitabu cha mwanafunzi = the student's book
• mtihani wa leo = today's exam
• asilimia ya wanafunzi = percentage of students

So the form of of in Swahili is not always the same; it changes with noun class.

The singular is mwanafunzi.

So:

• mwanafunzi = student
• wanafunzi = students

This is a very common noun-class pattern for people:

• m- in the singular
• wa- in the plural

Examples:

• mwalimu / walimu = teacher / teachers
• mtoto / watoto = child / children
• mwanafunzi / wanafunzi = student / students

The wa- at the beginning of walifaulu is the subject marker for a plural noun referring to people, here wanafunzi.

So:

• wa- = they
• -li- = past tense
• faulu = pass / succeed

Together:

• walifaulu = they passed

Even though the sentence begins with asilimia kubwa, the verb is agreeing with wanafunzi as the people who actually did the action.

Yes:

• wa- = they
• -li- = past tense
• faulu = pass / succeed

So:

• wa-li-faulu = they passed

This is very normal in Swahili. A lot of information gets packed into one verb word.

The infinitive is:

• kufaulu = to pass / to succeed

Because in Swahili, the subject marker, tense marker, and verb stem are usually written together as one verb word.

So Swahili writes:

• walifaulu not
• wali faulu

This is standard Swahili spelling.

The same happens in many other verbs:

• walisoma = they studied
• walikuja = they came
• waliandika = they wrote

Here faulu means to pass or to succeed.

In this sentence, it means the students passed the exam.

Common forms:

• kufaulu = to pass / succeed
• alifaulu = he/she passed
• walifaulu = they passed

You can also hear kufaulu mtihani specifically for to pass an exam.

In Swahili, mtihani is the direct object of faulu.

So:

• walifaulu mtihani = they passed the exam

No extra preposition is needed there.

That is a normal pattern in Swahili:

• kufaulu mtihani = to pass an exam
• kushinda mechi = to win a match

Literally, it means exam of today.

In natural English, that becomes today's exam.

Breakdown:

• mtihani = exam, test
• wa = of
• leo = today

So:

• mtihani wa leo = today's exam

This is a very common Swahili way to express what English often shows with 's.

Because the connector changes to agree with the noun before it.

• mtihani wa leo: the connector agrees with mtihani
• asilimia kubwa ya wanafunzi: the connector agrees with asilimia

So Swahili has several forms of this of connector, not just one fixed word.

That is why you see:

• wa
• ya
• cha
• za and others in different situations

Because the sentence is talking about one exam: today's exam.

So:

• mtihani = exam
• mitihani = exams

If there were several exams, you would expect the plural:

• mitihani ya leo = today's exams

But here the idea is one specific exam, so the singular mtihani is correct.

It says a large percentage of students, which is a bit broader and less exact than most students.

• asilimia kubwa = a large percentage
• asilimia nyingi would not sound right here for this meaning

If you want to say most students, Swahili often uses:

• wanafunzi wengi = many students / most students in some contexts

So asilimia kubwa ya wanafunzi emphasizes a proportion, not just a general large number.

Learners sometimes wonder about this because the sentence begins with asilimia kubwa. In practice, in a sentence like this, walifaulu agrees with wanafunzi, the people who passed.

That is the most natural way to understand this sentence:

• the students are the ones doing the action
• so the verb uses wa-

This kind of agreement is common when a phrase like a percentage of the students refers to actual people performing the action.