isya ga syuzyutu wo simasita.

They are particles, which show the role of each word in the sentence.

• 医者が = the doctor is the subject of the sentence
• 手術を = surgery / an operation is the object
• しました = did

So:

• が marks who did the action
• を marks what action was done

In this sentence, the doctor is the one doing the surgery.

This is a very common question.

• が marks the subject
• は marks the topic

Using が here simply presents the doctor as the person who performed the surgery.

• 医者が手術をしました。 = The doctor performed surgery.
• 医者は手術をしました。 would feel more like As for the doctor, he/she performed surgery or could imply contrast, depending on context.

In beginner sentences, が is often used when the focus is on who did it.

It is read:

いしゃ が しゅじゅつ を しました。

Word by word:

• 医者 = いしゃ
• 手術 = しゅじゅつ
• しました = しました

So the full reading is:

いしゃ が しゅじゅつ を しました。

しました is the polite past form of する, which means to do.

The verb forms are:

• する = do / to do
• します = do / will do, polite
• しました = did, polite past

In this sentence, 手術をする literally means to do surgery, which in natural English becomes to perform surgery.

So:

• 手術をしました = performed surgery

No. 手術 is a noun, not a verb.

It means:

• surgery
• an operation

Japanese often makes nouns into actions by adding する.

So:

• 勉強 = study
• 勉強する = to study

And here:

• 手術 = surgery
• 手術をする = to do / perform surgery

That is why the sentence uses 手術をしました instead of a single verb meaning operated.

It means the doctor performed surgery.

That is because:

• 医者が = the doctor is the subject, the one doing the action
• 手術をしました = did/performed surgery

If you wanted to say the doctor had surgery, the sentence would need a different structure, because the doctor would be the patient, not the performer.

So in this sentence, the doctor is the one carrying out the operation.

The patient is not stated in this sentence.

Japanese often leaves out information if it is already known from context or not important.

So 医者が手術をしました。 only tells us:

• who performed the surgery = the doctor
• what action happened = surgery was performed

It does not tell us who the surgery was performed on.

If you wanted to include that, you might say something like:

• 医者が患者に手術をしました。

But in real Japanese, that particular phrasing may sound unnatural depending on context, so native speakers often choose different wording to specify the patient more clearly.

Yes, to some extent.

Because Japanese uses particles, the roles are shown by が and を, so word order is more flexible than in English.

This sentence could also appear as:

• 手術を医者がしました。

That still means the doctor performed surgery, because:

• 医者が is still the subject
• 手術を is still the object

However, 医者が手術をしました is the more neutral and natural order here.

So yes, word order can change, but it may affect emphasis.

Normally, standard Japanese is written without spaces.

So the usual written form is:

医者が手術をしました。

The spaces are often added in beginner materials to make the sentence easier to read and to show where the words and particles are.

They are a learning aid, not standard Japanese punctuation.

Japanese usually does not use articles like a or the.

So 医者 can mean:

• a doctor
• the doctor

depending on context.

Also, Japanese nouns usually do not have a separate plural form like English does. Context tells you whether something is singular or plural.

So 医者が手術をしました could mean:

• A doctor performed surgery
• The doctor performed surgery

The exact English translation depends on the situation.

医者 is not gender-specific.

It simply means doctor.

So the sentence could refer to:

• a male doctor
• a female doctor

Japanese often leaves gender unstated unless it matters or is made clear by context.

Yes.

• 医者 is a plain, dictionary-style word for doctor
• お医者さん is a more polite or friendly everyday expression

In many contexts, お医者さん sounds softer and more natural in conversation, especially when talking to children or speaking casually about doctors.

But 医者 is perfectly normal in example sentences and general explanations.