Learn Hardcore Japanese: haha ha reizouko no doa ni memo wo harimasu. - My mother puts a note on the refrigerator door.

母は…: Sets “my mother” as the topic. You’re talking about what she does in general, or in this context.
母が…: Emphasizes that it is my mother (as opposed to someone else) who sticks the memo.

In a neutral, simple statement like this, 母は is very natural because the sentence is just describing what the mother does, without any special contrast or emphasis.

Why is it 冷蔵庫のドア instead of just 冷蔵庫?

冷蔵庫のドア literally means “the refrigerator’s door” or “the door of the refrigerator.”

In Japanese, の connects two nouns:

冷蔵庫 = refrigerator
ドア = door
冷蔵庫のドア = the door belonging to / part of the refrigerator

If you only said 冷蔵庫にメモを貼ります, it would literally mean “stick a memo to the refrigerator,” which sounds like putting it on any part of the fridge. 冷蔵庫のドア is more specific and matches what we usually say in English: “on the fridge door.”

Why is the particle に used after ドア when the English is “on the door”? Shouldn’t it be something like “on” instead?

In Japanese, に covers several meanings, including:

Location where something exists
- 机の上に本があります。= There is a book on the desk.
Location where an action is directed or where something ends up/sticks
- 壁にポスターを貼ります。= I put a poster on the wall.
- ドアにメモを貼ります。= I stick a memo on the door.

So in this sentence, ドアに corresponds to English “on the door” because the memo ends up attached to the door. Japanese uses に for this kind of “to/onto/onto the surface of” meaning.

There isn’t a separate basic particle that directly means “on” in this context; に is the normal choice.

Why is it メモを貼ります and not メモに貼ります?

Here we have two things:

メモ = the memo (the thing being attached)
ドア = the place/surface it is attached to

In Japanese, the pattern is:

[place] に [thing] を貼る
→ Stick/attach [thing] on [place].

So:

ドアにメモを貼ります。
= Stick a memo on the door.
メモ is the direct object being moved/attached → marked by を.
ドア is the location/surface where it is attached → marked by に.

If you said メモに貼ります, you would be saying “stick (something) onto the memo,” which is a different meaning and would require another object:
例: メモに写真を貼ります。 = I stick a photo onto the memo.

What is the dictionary/plain form of 貼ります, and what exactly does it mean?

The dictionary (plain) form is:

貼ります → 貼る (はる)

Basic meaning: to stick / to paste / to attach (flat objects) onto a surface.

Typical uses:

壁にポスターを貼る。= To put/stick a poster on the wall.
ノートにシールを貼る。= To stick a sticker in a notebook.
窓に紙を貼る。= To stick paper on the window.

So in メモを貼ります, it means “to stick a memo” (e.g., with tape or a magnet) onto the door.

What is the level of politeness of 貼ります, and how would I say this sentence in plain (casual) form?

貼ります is in the polite “-ます” form. It’s used in:

polite conversation with people you’re not very close to,
talking to elders, customers, teachers, etc.,
formal writing.

The plain (dictionary) form is:

貼る

To make the whole sentence plain:

母は冷蔵庫のドアにメモを貼る。

Same meaning, but it sounds more casual or neutral. You might say this among family or friends, or in a written explanation where casual/plain style is being used.

Is the word order fixed? Can I say 母はメモを冷蔵庫のドアに貼ります instead?

Japanese word order is fairly flexible as long as:

The verb comes at the end, and
Particles stay attached to the right words.

All of these are grammatically fine and mean the same thing:

母は冷蔵庫のドアにメモを貼ります。
母はメモを冷蔵庫のドアに貼ります。

The difference is nuance/emphasis:

Putting 冷蔵庫のドアに earlier can make the place feel a bit more like the setting.
Putting メモを earlier can lightly emphasize the memo.

But in everyday speech, both are natural; the original word order is probably the most common and neutral.

Why is は in 母は pronounced “wa” instead of “ha”?

The character は has:

the basic sound “ha” when it’s part of a word:
- 母（はは, haha）
- 花（はな, hana）
the sound “wa” when it’s used as the topic particle:
- 母は（はは wa）
- 私は学生です。(watashi wa gakusei desu.)

So in 母は, the first は (in 母) is “ha,” and the second は (particle) is “wa”:

はは wa れいぞうこのドアにメモをはります。

How do you read and pronounce each word in the sentence?

Reading with spaces and romaji:

母は冷蔵庫のドアにメモを貼ります。
はははれいぞうこのドアにメモをはります。

Word by word:

母（はは, haha）= mother (your own mother, stated neutrally)
は (wa) = topic particle
冷蔵庫（れいぞうこ, reizōko）= refrigerator
の (no) = “of” / possessive/connecting particle
ドア (doa) = door
に (ni) = location/target particle
メモ (memo) = memo, note
を (o / wo) = direct object particle
貼ります（はります, harimasu）= (polite present/future) stick/paste/attach

Full natural pronunciation:
はははれいぞうこのドアにメモをはります。

What is the difference between 母 and お母さん in this kind of sentence?

Both relate to “mother,” but the usage is different:

母（はは）:
- Used when talking about your own mother to an outsider.
- Sounds more neutral and slightly formal.
- You don’t usually use this to address your mother directly.
お母さん（おかあさん）:
- Used to address your mother: お母さん！ (Mom!)
- Also used when talking about someone else’s mother.
- Often used in the family as a title/name (“Mom”).

In a neutral description like this sentence (especially in writing or explanation), 母は冷蔵庫のドアにメモを貼ります。 is natural. In everyday spoken family Japanese, you might hear:

お母さんは冷蔵庫のドアにメモを貼る。

Is 母 the subject or the topic of the sentence?

母 is grammatically the topic because it is marked by は.

Japanese often leaves the true grammatical subject (marked by が) unspoken if it’s obvious. In a simple sentence like this, the topic and the doer of the action are the same person, so in English we naturally treat 母 as the subject:

Japanese structure:
- Topic: 母は
- Verb phrase: 冷蔵庫のドアにメモを貼ります。
English interpretation:
- Subject: My mother
- Verb: sticks
- Object: a memo
- Location phrase: on the refrigerator door.

So technically it’s the topic, but functionally it also corresponds to the subject in English.

Could this sentence also be used to mean a habitual action, like “My mother usually/still/always sticks a memo on the refrigerator door”?

Yes. The non-past ます form (貼ります) can express:

Present/future single action (depending on context):
- “(She) will stick a memo on the door.”
Habitual action (something someone does regularly):
- “(She) sticks memos on the fridge door (as a habit).”

Japanese relies on context to distinguish these meanings. In isolation:

母は冷蔵庫のドアにメモを貼ります。
is most naturally understood as either a general statement about what she does, or as a simple narrative “she sticks a memo on the refrigerator door,” depending on the surrounding conversation.

How would I say “There is a memo stuck on the refrigerator door,” focusing on the existing state, not the action?

To describe the resulting state (that something is attached and is there now), Japanese often uses ～てある with transitive verbs like 貼る:

冷蔵庫のドアにメモが貼ってあります。
= There is a memo stuck on the refrigerator door.
(Literally: “A memo has been stuck on the fridge door and is there.”)

Key differences:

メモを貼ります。 = (Someone) sticks a memo. (Action-focused)
メモが貼ってあります。 = A memo is (in a state of being) stuck there. (Result/state-focused)

Could I say 冷蔵庫にメモを貼ります without mentioning ドア? Does it sound natural?

Yes, you can say:

冷蔵庫にメモを貼ります。

This means “(I) stick a memo on the refrigerator,” and is grammatically correct and natural. It just sounds less specific. It could mean:

On the door,
On the side,
Anywhere on the fridge.

冷蔵庫のドアにメモを貼ります。 explicitly says “on the door of the fridge”, which matches typical real-life behavior, so it often sounds more natural if you specifically mean the door.