kaikei ga owattara, motikaeri no piza wo uketorimasu

Because 終わる is an intransitive verb: it means to end / to be finished, not to finish something.

So in Japanese, the thing that ends is marked with が:

• 会計が終わる = the payment/check-out ends
• not 会計を終わる

If you wanted a transitive version, you would use a verb like 終える:

• 会計を終えたら = after finishing the payment

So 会計が終わったら literally feels like when the payment is finished.

終わったら is:

• 終わった = past/plain form of 終わる
• ら = the conditional part of 〜たら

Together, 〜たら often means:

• when ...
• after ...
• if ...

In this sentence, it means when/after the payment is finished.

So:

• 会計が終わったら、... = When the payment is done, ...

Here it is not a hypothetical if so much as a sequence: first the payment finishes, then the pizza is picked up.

This is a very common point in Japanese.

In 〜たら, the first verb takes the past short form, but that does not necessarily make the whole sentence past tense.

So:

• 終わったら does not mean after it ended in a strictly past-time sense
• it means when/after it has ended

This is just how the 〜たら pattern is built.

Compare:

• 家に帰ったら、勉強します。 = When I get home, I’ll study.

Even though 帰った is past form, the whole sentence is about the future.

Here, 会計 means something like:

• the payment
• the check-out
• the bill/payment process

In a restaurant or shop context, 会計 often refers to settling the bill.

Depending on context, English might translate it as:

• After I pay
• After checking out
• Once the payment is finished

You may also hear お会計, which is a more polite version.

持ち帰り means takeout / takeaway.

So:

• 持ち帰りのピザ = takeout pizza / a pizza to take home

The particle の links nouns and makes one noun describe another.

So this is literally something like:

• the pizza for takeout
• the takeout pizza

This is similar to:

• 日本の車 = Japanese car
• 学校の先生 = school teacher

Here, 持ち帰り acts like a noun modifying ピザ.

Yes. 持ち帰り comes from the verb 持ち帰る, which means to take home.

As a noun, 持ち帰り means:

• takeout
• taking home

In everyday situations, Japanese also commonly uses:

• テイクアウト

So depending on the context, you might hear either:

• 持ち帰りのピザ
• テイクアウトのピザ

Both can refer to takeout pizza, though テイクアウト is especially common in modern everyday speech.

Because ピザ is the direct object of 受け取ります.

• ピザを受け取ります = receive/pick up the pizza

The particle を marks the thing being received.

So the structure is:

• 持ち帰りのピザ = the takeout pizza
• を = object marker
• 受け取ります = receive / pick up

Literally, 受け取ります means receive.

But in this kind of situation, a more natural English translation is often:

• pick up
• collect

So in context:

• 持ち帰りのピザを受け取ります = I pick up the takeout pizza = I collect the takeout pizza

It is often used when you receive something that has been prepared, handed over, delivered, or reserved.

For example:

• 荷物を受け取る = receive a package
• チケットを受け取る = receive/pick up a ticket

Because 受け取る has the nuance of accepting/receiving something from someone.

By contrast, 取る is much broader and can mean:

• take
• get
• pick up
• remove
• pass an exam
• take a photo

So 受け取る is more specific and natural when something is being handed over to you, such as:

• an order
• a package
• a document
• a ticket

For a pizza order at a counter, 受け取る is a very natural choice.

Japanese often omits the subject when it is clear from context.

So this sentence does not explicitly say:

• I
• you
• we

But from the situation, it is usually understood as something like:

• I will pick up the takeout pizza after paying
• or you pick up the takeout pizza after paying

The exact subject depends on who is speaking and the surrounding context.

This omission is completely normal in Japanese.

受け取ります is the polite non-past form.

Japanese often uses 〜ます form in:

• polite speech
• customer service
• neutral written explanations
• formal conversation

So:

• 受け取る = plain form
• 受け取ります = polite form

The non-past form here can mean:

• present habitual
• future

In this sentence, it has a future meaning:

• will pick up / will receive

The comma is not grammatically required, but it is very common and helpful.

It separates the condition/time clause from the main action:

• 会計が終わったら、持ち帰りのピザを受け取ります。

This makes it easier to read:

• first: when the payment is finished
• then: pick up the takeout pizza

Without the comma, the sentence is still understandable.

Yes.

In English, 〜たら often overlaps with both:

• when
• after

So this sentence could be understood as:

• When the payment is finished, I’ll pick up the takeout pizza.
• After paying, I’ll pick up the takeout pizza.

The exact English wording depends on what sounds most natural in context.

The important idea is sequence:

1. the payment finishes
2. the pizza is received/picked up