torakku ga kaisya ni tukimasita.

Not in normal Japanese writing. A native speaker would usually write this as:

トラックが会社に着きました。

Spaces are often added in beginner materials to make the particles and word boundaries easier to see.

トラック is a loanword from English truck, and loanwords are usually written in katakana.

Katakana is commonly used for:

• borrowed foreign words
• some onomatopoeia
• emphasis
• scientific names, etc.

So トラック is the normal way to write truck in Japanese.

が marks the grammatical subject of the sentence.

So in this sentence, トラックが means that the truck is the thing that arrived.

A very natural beginner way to think about it is:

• が = identifies what did the action / what the sentence is about grammatically right now

Also, 着く is an intransitive verb, so it does not take a direct object with を. That is why you get トラックが rather than トラックを.

Yes, in some contexts, but the nuance changes.

• トラックが会社に着きました。
  This sounds like the truck arrived at the company with focus on the truck as the subject or as new information.

• トラックは会社に着きました。
  This sounds more like as for the truck, it arrived at the company, possibly contrasting it with something else.

So:

• が often introduces or highlights the subject
• は often marks the topic and can imply contrast or established information

Both can be grammatical, but が is very natural if you are simply reporting that the truck arrived.

Here, に marks the destination or point of arrival.

With 着く (to arrive), the place you arrive at is usually marked with に.

So:

• 会社に着きました = arrived at the company

This に is not marking an indirect object here. It is marking the destination.

With 着く (to arrive), に is the standard particle because it marks the exact destination reached.

• に = destination / point reached
• へ = direction toward

With movement verbs like 行く or 来る, both に and へ can often work:

• 会社に行く
• 会社へ行く

But with 着く, に is much more natural because arriving means you actually reached that place.

By itself, 会社 just means company. The sentence only says that the truck arrived at the company being referred to in context.

It does not automatically mean the truck’s company.

If you wanted to say the company’s truck, you would say:

• 会社のトラック

So in this sentence:

• トラック = the truck
• 会社に = at/to the company

They are separate parts.

着きました is the polite past form of 着く (つく), meaning to arrive.

Breakdown:

• dictionary form: 着く
• polite non-past: 着きます
• polite past: 着きました

So 着きました means arrived in polite speech.

Because 着く is a godan verb ending in -く.

For this type of verb:

• -く changes to -き before ます

So:

• 着く → 着きます → 着きました

This is a very common pattern:

• 書く → 書きます
• 聞く → 聞きます
• 着く → 着きます

Not exactly.

• 行く = to go
• 来る = to come
• 着く = to arrive

So 着く focuses on reaching the destination, not on the movement itself.

For example:

• 会社に行きました。 = went to the company
• 会社に着きました。 = arrived at the company

In English, both may fit similar situations, but in Japanese the choice changes the focus.

The basic order here is:

subject + destination + verb

So:

• トラックが = subject
• 会社に = destination
• 着きました = verb

Japanese word order is more flexible than English, but the verb usually comes at the end.

Yes, very often.

If it is already clear from context, Japanese often leaves out the subject. For example, someone might simply say:

会社に着きました。

That could mean:

• (The truck) arrived at the company
• (We) arrived at the company
• (He/She/They) arrived at the company

The listener figures it out from context. In your sentence, トラックが is included to make the subject explicit.

Usually yes, but the exact English wording depends on context.

会社 refers to a business company or firm. In a sentence like this, English might say:

• the company
• the office
• the company site
• the business

depending on what the situation actually is.

So the Japanese word is straightforward, but the most natural English translation can vary a little based on context.