kakariin ga mondai ni taisyosita.

It is read:

かかりいん が もんだい に たいしょした。

Word by word:

• 係員 = かかりいん
• が
• 問題 = もんだい
• に
• 対処した = たいしょした

係員 means something like staff member, attendant, clerk, or person in charge, depending on the situation.

It is a fairly general word for a person working in an official or assigned role. For example, it could refer to:

• a station attendant
• an office staff member
• an event staff worker
• a clerk handling a specific task

So it is not a personal title like a name; it is more a role-based noun.

が marks 係員 as the grammatical subject of the sentence.

So the structure is:

• 係員が = the staff member is the one who did the action
• 問題に対処した = dealt with the problem

A learner often wonders why this is not は. The short answer is:

• が simply identifies the subject
• は would mark the topic and can give a slightly different nuance

Compare:

• 係員が問題に対処した。
  = The staff member dealt with the problem.
• 係員は問題に対処した。
  = As for the staff member, they dealt with the problem.

In an isolated example sentence, が is very natural.

In 問題に対処する, the particle に marks what the action is directed toward.

So:

• 問題に = to/for/regarding the problem
• 対処する = to deal with / to handle / to cope with

This is just the normal pattern used with 対処する:

• トラブルに対処する = deal with trouble
• 危機に対処する = deal with a crisis
• 問題に対処する = deal with a problem

Even though English uses with in deal with, Japanese uses に here.

対処した is the past form of the verb 対処する.

Breakdown:

• 対処 is a noun-like Sino-Japanese word meaning dealing/handling
• する turns it into a verb: 対処する = to deal with
• した is the plain past form of する

So:

• 対処する = deal with
• 対処した = dealt with

This is a very common pattern in Japanese:

• 勉強する → 勉強した
• 利用する → 利用した
• 対処する → 対処した

They are similar, but not exactly the same.

• 対処する often means to deal with a problem or situation, especially by taking measures
• 対応する often means to respond to, handle, or support, and is very common in service/business contexts

For example:

• 問題に対処する = deal with a problem
• 問い合わせに対応する = respond to an inquiry

In many situations they overlap, but 対処する can sound a bit more like taking action against an issue, while 対応する often emphasizes responding appropriately.

した is the plain past form.
しました is the polite past form.

So the sentence as written is in plain style:

• 係員が問題に対処した。

A polite version would be:

• 係員が問題に対処しました。

Neither changes the core meaning. The difference is style:

• した = plain, neutral dictionary/example style, casual writing, narration
• しました = polite speech or polite writing

Textbooks often show plain forms in example sentences because they are the basic grammatical forms.

The basic order here is:

係員 が 問題 に 対処した。

This is very natural, but Japanese word order is more flexible than English as long as the particles make the roles clear.

For example, you could also say:

• 問題に係員が対処した。

That still means the staff member dealt with the problem, because:

• が still marks the subject
• に still marks the target of 対処する

However, the original order is the most straightforward and neutral.

Yes. Japanese often omits information that is clear from context.

So you could simply say:

• 問題に対処した。

That means:

• [Someone] dealt with the problem
• or [I/they/he/she] dealt with the problem

The subject is omitted because Japanese does not always need to state it explicitly if the listener can infer it.

It is grammatically in the plain style because of した, but the vocabulary itself is somewhat formal or official-sounding.

Why?

• 係員 is a formal-ish word for staff/attendant
• 対処する is also a formal or written-style verb compared with more casual everyday wording

So the sentence feels like:

• plain in grammar
• somewhat formal in vocabulary

A more conversational sentence might use different wording depending on context, but this sentence sounds very natural in reports, explanations, or written examples.

The kanji are:

• 対 = against, toward, opposite, facing
• 処 = place, deal with, handle, process

Together, 対処 gives the idea of dealing with something or handling a situation/problem.

You do not need to interpret the kanji literally every time, but knowing them can help you remember the word:

• 問題に対処する = deal with a problem
• 困難に対処する = cope with difficulty