sensei ha gakuseizenin ni byoudou ni situmon wo simasu.

The teacher asks questions to all the students equally.

Breakdown of sensei ha gakuseizenin ni byoudou ni situmon wo simasu.

• は: topic particle
• を: direct object particle
• 先せん生せい: teacher
• に: indirect object particle
• 質問しつもん: question
• 質問しつもん を する: to ask
• 平等びょうどう に: equally
• 学生がくせい全員ぜにん: all the students

Questions & Answers about sensei ha gakuseizenin ni byoudou ni situmon wo simasu.

In this sentence, what role does each part play grammatically?

The sentence:

先生 は 学生全員 に 平等 に 質問 を します。

Breakdown:

• 先生 – teacher
• は – topic marker: as for the teacher / the teacher…
• 学生全員 – all (of the) students
• に – marks the indirect object / target: to all the students
• 平等 – equality, fairness
• に – turns 平等 into an adverb: equally / fairly
• 質問 – question; questioning
• を – object marker: marks 質問 as the direct object of する
• します – polite form of する, to do: to do questioning → to ask questions

Very literally:
As for the teacher, to all the students, equally, (he/she) does questioning.
Natural English: The teacher asks questions equally to all the students.

Why is it 先生は and not 先生が?

は marks the topic, not just the grammatical subject.

• 先生は… sets up “the teacher” as what we’re talking about. It has a broad, thematic feel:
  
  • (Speaking of) the teacher, (he/she) asks all the students questions equally.

If you used 先生が, it would feel more like you’re focusing on who does the action, often contrasting with others:

• 先生が学生全員に平等に質問をします。
  → It’s the teacher who asks all the students questions equally. (e.g. not the TA, not the students themselves)

In neutral narration or explanation, 先生は is more natural when you’re simply describing what the teacher does as a general fact or habit.

Why are there two に particles, in 学生全員に and 平等に? Are they doing the same thing?

They are the same particle に, but used in two different roles.

1. 学生全員に

   • Here に marks an indirect object / target / recipient.
   • Rough meaning: to / for all the students.
   • Pattern: [person] に [something] を する → do [something] to [person]

2. 平等に

   • Here に turns 平等 into an adverb.
   • Rough meaning: equally / in an equal way / fairly.
   • Pattern: [noun/na-adjective] に [verb] → do [verb] in an X way / X-ly

So:

• 学生全員に → tells who the questions are directed to.
• 平等に → tells how the teacher asks (the manner).

How can 平等, which is a noun, become “equally” with に?

In Japanese, many words that are nouns (and na-adjectives) can be turned into adverbs by adding に.

• 平等 – equality; fairness (noun)
• 平等な – equal, fair (na-adjective: 平等な社会 “an equal society”)
• 平等に – equally, fairly (adverb: 平等に扱う “treat (people) equally”)

This pattern is very common:

• 静か → 静かに話す – to speak quietly
• 簡単 → 簡単にできる – can do it easily/simply
• 安全 → 安全に運転する – to drive safely

So 平等に質問をします means (the teacher) asks questions in an equal/fair way.

Why is there an を after 質問? Can’t I just say 質問します?

Both 質問します and 質問をします are used in real Japanese:

• 質問をする is a light-verb construction:
  質問 (noun: question, questioning) + を + する (do)
  → to do a question / questioning → to ask a question / ask questions
• 質問する is the same idea with the を dropped and the verb fused.

In practice:

• 質問をします
• 質問します

These are both correct and very common. The nuance difference is tiny; 質問をします can feel a bit more explicit or slightly more formal/written, but for most learners you can treat them as interchangeable in meaning: to ask (a) question(s).

What exactly does 質問をします mean? Who is asking whom in this pattern?

質問をする on its own means “to ask a question / to question”.

To show who is being asked, Japanese uses に:

• 先生は学生に質問をします。
  → The teacher asks the student questions.
  (literally: The teacher does questioning to the student.)

So in your sentence:

• 先生は 学生全員に 平等に 質問をします。

The structure is:

• 先生は – the one who asks (topic/subject)
• 学生全員に – the ones being asked (indirect object / target)
• 質問をします – does questioning → asks questions

If you wanted to specify what the question is about, you could add a を or について phrase:

• 先生は学生全員に宿題について質問をします。
  → The teacher asks all the students questions about the homework.

What does 学生全員に literally mean, and how is it different from 全ての学生 or みんな?

学生全員に literally:

• 学生 – students
• 全員 – all members / everyone (in a group)
• 学生全員 – all the students; every student (in the group being talked about)
• 学生全員に – to all the students / to every student

Comparisons:

1. 学生全員に

   • Focuses on everyone in that specific group of students.
   • Very natural for things done to each member:
     学生全員に配る – to distribute to all the students.

2. 全ての学生に

   • More literally “to all the students”.
   • Slightly more formal or written-sounding than 学生全員に, but often interchangeable.
   • Emphasizes 100% of the set.

3. みんなに

   • Informal, conversational: “to everyone”.
   • Doesn’t by itself say they are students; context must supply that.
   • E.g. among classmates you might say:
     先生はみんなに平等に質問をします。

In your sentence, 学生全員に clearly and naturally says to every student (in the class / group).

Is the word order fixed? Can I move 平等に or 学生全員に around?

Japanese word order is flexible inside the middle part of the sentence, but the verb usually comes at the end.

Your original:

• 先生は 学生全員に 平等に 質問をします。

You can reorder the non-verb elements without changing the basic meaning:

• 先生は 平等に 学生全員に 質問をします。
• 先生は 学生全員に 質問を 平等に します。 (less common, but possible)
• 先生は 平等に 質問を 学生全員に します。 (sounds a bit awkward)

Natural, smooth orders are usually:

• 先生は学生全員に平等に質問をします。
• 先生は学生全員に質問を平等にします。 (a bit marked/emphatic on 平等に)

General guidelines:

• は/が/を/に chunks can usually be swapped among themselves.
• The main verb (します) stays near the end.
• Adverbs like 平等に tend to appear before the main verb or close to what they modify.

For learners, using the original order is perfectly fine and sounds natural.

What does 平等に modify here – the teacher, the students, or the act of asking?

平等に is an adverb, so it modifies the verb phrase, i.e. the act of asking questions.

• It does not mean “the teacher is fair” (as an adjective).
• It does not directly mean “the students are equal”.
• It means the teacher performs the action (asking questions) in an equal/fair way toward the students.

So:

• 学生全員に平等に質問をします。
  → (The teacher) asks all the students questions in an equal way.
  (no student is favored or ignored)

Is 先生 here “the teacher”, “a teacher”, or “my/our teacher”?

Japanese doesn’t have articles like a / the, so 先生 can correspond to any of them, depending on context.

Possible readings:

• the teacher (the one we both know we’re talking about, e.g. the class’s teacher)
• a teacher (if introduced for the first time in a story)
• my/our teacher (very common in a school context, where 先生 often implies “our teacher”)

In a typical classroom or textbook context, the most natural English translation is:

• The teacher asks all the students questions equally.

But grammatically, Japanese itself does not choose a vs the vs my; that comes from context.

How polite is this sentence, and how would it change in casual speech?

The verb is します, the polite -ます form of する, so the sentence is in polite/plain-formal style (丁寧語).

• 先生は学生全員に平等に質問をします。
  – polite, appropriate for talking to someone you should respect or in writing.

Casual versions:

1. Simply drop the ます:

   • 先生は学生全員に平等に質問をする。
     (plain form, neutral narrative/casual)

2. In very casual speech (among close friends), you might even shorten further:

   • 先生、学生全員に平等に質問する。 (dropping は in speech)
   • Or use 質問するんだ etc., depending on context.

The main change in politeness is します → する; the rest of the sentence stays the same.

Could I say 先生は学生全員を平等に質問します, using を after 学生全員 instead of に?

That would not be natural Japanese.

The verb 質問する usually follows this pattern:

• [person] に 質問する → “to ask [person] (a question)”
  e.g. 先生は学生に質問する。 – The teacher asks the student.

So:

• 学生全員に質問をします。 – correct (ask to all the students)
• 学生全員を質問します。 – sounds wrong/unnatural

Why? Because を marks a direct object, but in Japanese the person who is asked is normally marked by に, not を. With 質問する, を is for what is being questioned (if specified), not who is being questioned.

Correct patterns:

• 学生全員に質問をする。 – ask all the students (something)
• 宿題の内容を質問する。 – ask about the homework content
• 学生全員に宿題の内容を質問する。 – ask all the students about the homework content

Can I replace 質問をします with 聞きます? What’s the difference?

You sometimes can, but they’re not identical in nuance.

• 質問をします / 質問します
  – explicitly “to ask a question / to question (someone)”
  – formal/neutral, often used in classrooms, meetings, interviews, etc.

• 聞きます (from 聞く)
  – has two main meanings:

  1. to listen / to hear
  2. to ask (something of someone)

So in the “ask” sense, you could say:

• 先生は学生全員に公平に聞きます。
  This could mean “The teacher asks all the students (something) fairly”, but without context it more often suggests “listens (to them)” or sounds a bit vague.

When you want to clearly express asking questions, especially in a classroom/testing context, 質問（を）する is more precise and natural:

• 先生は学生全員に平等に質問をします。
  → clearly: The teacher asks questions equally to all the students.

So:

• Use 質問（を）する when you want to emphasize asking questions.
• Use 聞く more for listening or asking (to get information) in a looser, less formal sense, often with 何を聞く / 先生に聞く etc.