torihiki ga owarimasita.

It is read:

とりひき が おわりました

• 取引 = とりひき
• が = が
• 終わりました = おわりました

So the full sentence is:

とりひき が おわりました。

取引 usually means transaction, deal, business dealing, or trade.

Depending on context, it could refer to:

• a commercial transaction
• a business deal
• trading activity
• dealings between two parties

So in this sentence, 取引 is the thing that has ended or been completed.

が marks 取引 as the thing that ended.

Since 終わる means to end and is an intransitive verb, the thing that ends is commonly marked with が.

So:

• 取引が終わりました = The transaction ended / is over
• literally, As for the transaction, it ended

Using が is very natural when you are simply stating that something happened.

This is an important grammar point.

• 終わる = to end (intransitive)
• 終える = to finish something (transitive)

In this sentence, the transaction itself is being described as ending, so Japanese uses the intransitive verb:

• 取引が終わりました = The transaction ended

If you used 終える, you would need someone to actively finish something:

• 私たちは取引を終えました = We finished the transaction

So 終わりました is used because the sentence focuses on the event being over, not on a person causing it to finish.

It can match any of those in English depending on context.

Japanese past polite form -ました often covers ideas that English expresses in different ways:

• ended
• has ended
• is over

So 取引が終わりました could naturally be translated as:

• The transaction ended.
• The transaction has ended.
• The transaction is over.

English chooses among these based on context, but the Japanese sentence itself is normal for all of them.

Yes. 終わりました is in the polite past form.

Compare:

• plain: 取引が終わった
• polite: 取引が終わりました

The sentence you were given is appropriate in normal polite conversation, business situations, and formal announcements.

Yes, but the nuance changes slightly.

• 取引が終わりました
  This simply reports that the transaction ended.

• 取引は終わりました
  This puts 取引 in topic position and may sound like As for the transaction, it has ended.

Using は can sometimes suggest contrast, depending on context, such as:

• 取引は終わりましたが、支払いはまだです。
  The transaction is finished, but the payment is not yet.

So が is the more neutral choice when you are just stating the event.

Because Japanese often leaves out information that is understood from context.

In English, you might say:

• We finished the deal
• They completed the transaction
• The transaction is over

Japanese often does not mention the people involved unless necessary. Here, the focus is on the transaction itself, so the sentence only says that the transaction ended.

This is very normal in Japanese.

Yes, it is natural.

終わる is commonly used for things such as:

• meetings
• classes
• events
• negotiations
• transactions

So 取引が終わりました is a normal way to say that a transaction or deal has come to an end.

In some business contexts, you may also hear more formal alternatives like:

• 取引が終了しました = The transaction has concluded
• 取引が完了しました = The transaction has been completed

But 終わりました is perfectly understandable and natural.

They are similar, but their tone and nuance differ.

• 終わりました
  General, common, straightforward: ended / is over

• 終了しました
  More formal or technical: concluded / terminated / ended

• 完了しました
  Stronger sense of completion: has been completed

For a transaction:

• 取引が終わりました = the transaction ended / is over
• 取引が終了しました = the transaction has concluded
• 取引が完了しました = the transaction has been completed

In business or system messages, 完了しました and 終了しました are often more common than 終わりました.

By itself, it mainly means that the transaction came to an end. It does not automatically tell you whether it ended successfully or unsuccessfully.

That depends on context.

For example:

• If you are talking about a normal sales process, it may imply successful completion.
• If you are talking about negotiations, it could simply mean they ended, not necessarily successfully.

If you want to clearly say it was successfully completed, Japanese might use wording like:

• 取引が完了しました
• 取引が成立しました = The deal was concluded / finalized

So 終わりました tells you the ending happened, but not always the result.

Not with 終わる.

Since 終わる is intransitive, it does not normally take を for the thing that ends. So:

• natural: 取引が終わりました
• unnatural: 取引を終わりました

If you want to use を, use a transitive verb such as 終える:

• 取引を終えました = finished the transaction

So the particle depends on the verb:

• 終わる → thing marked by が
• 終える → thing marked by を