Learn Hardcore Japanese: kinou ha sensei ni sanmai no purinto wo moraimasita. - I received three handouts from the teacher yesterday.

Both are correct. 昨日は adds a slight emphasis on “yesterday” as the theme, and can also imply contrast with other times (e.g., “Yesterday I got three; today I got none.”).

Why is there no 私 (I) in the sentence?

Japanese often omits pronouns when they’re clear from context.

The full underlying pattern is:

（私は）先生に三枚のプリントをもらいました。
→ (I) received three handouts from my teacher.

Because it’s obvious the speaker is the one receiving something from their own teacher, 私は is left out. Including 私は is not wrong, but it can sound a bit heavy or repetitive if the context already makes it clear who is speaking.

What does 先生に do here? Why に and not another particle?

With the verb もらう (to receive), the person you receive from is marked with に:

A は B に C をもらう
→ A receives C from B.

So:

先生に = from the teacher
三枚のプリントを = three handouts (as object)
もらいました = received

Putting it together: I received three handouts *from my teacher yesterday.*

に here marks the source/giver with もらう.

Can I use 先生から instead of 先生に? Is there any difference?

Yes, you can also say:

昨日は先生から三枚のプリントをもらいました。

Both 〜に and 〜から can mark the giver with もらう.

Nuance (subtle, not huge):

先生に〜もらう
– Slightly more neutral and common pattern with もらう.
先生から〜もらう
– Can slightly emphasize the “from-ness,” like “from the teacher (as the source).”

For everyday conversation, they’re both fine and often interchangeable. Many learners start by memorizing X に～をもらう as the basic pattern.

What is 三枚? Why do we need a counter here?

三枚（さんまい） is “three flat things”, using the counter 枚（まい）.

In Japanese, you need counters when counting most kinds of objects. 枚 is used for thin, flat items, such as:

sheets of paper
tickets
plates
photos, etc.

So 三枚のプリント literally means “three-sheet(s) of handout”, i.e., three handouts.

The structure is:

三 (3)
枚 (counter for flat objects)
together 三枚 = three flat objects

Why is there a の in 三枚のプリント? Could I say 三枚プリント or プリント三枚?

三枚のプリント is “three handouts,” where:

三枚の is like an adjective phrase modifying プリント.

You have three main options:

三枚のプリント
– Very natural, especially in writing or careful speech.
– Literally “three (flat) sheets of handout.”
プリントを三枚もらいました。
– Also very common: noun + を
- number + counter + verb.
  – “(I) received three handouts.”
プリント三枚
– Also possible, especially in casual speech.
– Sounds a bit clipped / list-like: “three handouts.”

In this sentence, 三枚のプリント is perfectly standard and clear for learners.

What does プリントを with を mean here?

を is the direct object marker. It marks what is being received:

プリント = handout(s)
プリントをもらいました = “(I) received handout(s).”

In the full phrase:

三枚のプリントをもらいました。
→ received three handouts.

So を just shows that プリント is the thing directly affected by the verb もらいました.

How flexible is the word order? Can I move parts of the sentence around?

Japanese word order is fairly flexible as long as the verb comes last and particles stay attached to their words.

Your sentence:

昨日は　先生に　三枚のプリントを　もらいました。

Some natural variations:

昨日は先生にプリントを三枚もらいました。
昨日、先生に三枚のプリントをもらいました。
先生に昨日三枚のプリントをもらいました。 (OK, though the original feels smoother)
先生に三枚のプリントを昨日もらいました。 (possible but sounds a bit marked / unusual)

What generally must stay:

The verb at the end: …もらいました。
Particles stick to their words: 先生に, プリントを, 昨日は.

Within those constraints, ordering time, place, and object phrases is somewhat flexible and driven by emphasis and natural flow.

Why use もらいました and not くれました?

Both もらう and くれる describe giving/receiving, but from opposite viewpoints.

もらう = “to receive (for me/us)”
Pattern: (receiver) は (giver) に (thing) をもらう
→ Focus on the receiver.
くれる = “to give (to me/us)”
Pattern: (giver) が (receiver に) (thing) をくれる
→ Focus on the giver doing something for the speaker.

Your sentence:

（私は）先生に三枚のプリントをもらいました。
→ I received three handouts from my teacher.

If you use くれる, you’d rephrase it:

先生が（私に）三枚のプリントをくれました。
→ The teacher gave me three handouts.

Same real-world event; different grammatical focus. The original sentence centers on me as the receiver, which is natural with もらう.

Why is it もらいました (polite) instead of もらった (plain)? How does the form change?

もらいました is the polite past form of もらう.

Dictionary form: もらう (to receive)
Polite non-past: もらいます (receive / will receive)
Polite past: もらいました (received)
Plain past: もらった (received, casual)

So:

Polite: 昨日は先生に三枚のプリントをもらいました。
Casual: 昨日は先生に三枚のプリントをもらった。

You choose polite vs casual based on who you’re talking to (teacher, boss → polite; close friends → casual).

Is it okay to use もらう when talking about receiving something from a teacher? Is there a more polite version?

もらう is grammatically fine here, even with a teacher, but in more formal or humble situations, Japanese often uses the humble verb いただく instead of もらう when the speaker receives something.

Humble version:

昨日は先生に三枚のプリントをいただきました。
→ I humbly received three handouts from my teacher.

Nuance:

もらいました – polite, neutral.
いただきました – more polite and humble, emphasizing respect toward the teacher.

In everyday casual speech to friends, もらう / もらった is very natural. Talking formally about what your teacher gave you (e.g., in a presentation), いただく / いただきました sounds more respectful.

How do you read (pronounce) the whole sentence?

One natural reading is:

きのうはせんせいにさんまいのプリントをもらいました。

Word by word:

昨日 – きのう
先生 – せんせい
三枚 – さんまい
プリント – ぷりんと
もらいました – もらいました (もらい + ました)

Stress-wise, Japanese has relatively even rhythm compared to English—try to give each mora (sound unit) roughly equal length:

き・の・う｜は｜せ・ん・せ・い｜に｜さ・ん・ま・い｜の｜ぷ・り・ん・と｜を｜も・ら・い・ま・し・た

Why is 昨日 written with kanji instead of hiragana (きのう)? Is きのう also acceptable?

Both are acceptable:

昨日は先生に三枚のプリントをもらいました。
きのうは先生に三枚のプリントをもらいました。

In modern Japanese:

昨日 / 今日 / 明日 are very common kanji and often written in kanji.
In beginner materials or to emphasize pronunciation, they might be written in hiragana.

Reading:

In this everyday context, 昨日 is read きのう, not さくじつ.
さくじつ is a more formal/official reading, used in news, business, etc., and the rest of the sentence would usually be more formal if you used it.