dekakeru mae ni sitakusite, wasuremono ga nai ka kakuninsimasu.

With 前に, Japanese normally uses the dictionary form of the verb:

• 出かける前に = before going out

This is because the action in the 前に clause has not happened yet at the time of the main action.

Compare:

• 出かける前に = before going out
• 出かけた後で = after going out

So 前に tends to pair with the plain non-past form, while 後で / あとで often pairs with the past form.

前に means before.

In this sentence, 出かける前に sets the time for the actions that follow:

• 支度して = get ready
• 忘れ物がないか確認します = check whether I haven’t forgotten anything

So the whole idea is: these things happen before going out.

The て-form is being used to connect actions in sequence.

• 支度して、確認します
• get ready, and check ...

It shows that one action happens and then the next action follows. In this sentence:

1. 出かける前に — before going out
2. 支度して — get ready
3. 忘れ物がないか確認します — check whether there’s anything forgotten

So 支度して works like and then get ready / after getting ready depending on context.

Yes, both can mean something like prepare or get ready, but they are used a little differently.

• 支度する often means to get oneself ready or to make the necessary arrangements
• 準備する is broader and often means to prepare something

In this sentence, 支度して feels natural because it refers to getting ready before going out.

For example:

• 出かける支度をする = get ready to go out
• 旅行の準備をする = prepare for a trip

Both may work in some contexts, but 支度 is especially common for personal readiness.

Because ない is functioning like there is not / does not exist, not as an action verb taking を.

• 忘れ物がない = there are no forgotten items / I haven’t left anything behind

Here, 忘れ物 is the thing whose existence is being checked, so が is natural.

This is similar to:

• 時間がない = there is no time
• 問題がない = there is no problem

So がない is the normal pattern.

忘れ物 literally means a forgotten thing or something left behind.

In actual use, it often has a general sense:

• 忘れ物がないか = whether there is anything forgotten / whether I’ve forgotten something

So even though it looks singular in English, Japanese often leaves number vague. Depending on context, it can mean:

• no forgotten item
• no forgotten items
• nothing left behind

All of those fit the sentence.

Here, か marks an embedded question:

• 忘れ物がないか確認します
• I check whether there are any forgotten items
• I check if I haven’t forgotten anything

So か is not being used as a sentence-ending question marker. Instead, it turns the clause before it into something like whether ... or if ....

Other examples:

• 雨が降るか知りません = I don’t know whether it will rain
• 来るか確認します = I’ll check whether they are coming

Because the clause before か is in plain form, which is normal for embedded questions.

• 忘れ物がないか確認します = I check whether there’s anything forgotten

Japanese usually uses plain forms before particles like か in this kind of structure.

A more polite style can appear in some contexts, but the plain form is the standard grammar here.

So even though the sentence ends politely with 確認します, the embedded clause stays plain:

• ないか
• not ありませんか in this structure

In this sentence, 確認します is best understood as check.

• 忘れ物がないか確認します = check whether I forgot anything

The verb 確認する often means:

• to confirm
• to check
• to verify
• to make sure

In everyday English, check or make sure is usually the most natural translation here.

The subject is omitted because Japanese often leaves it out when it is obvious from context.

So this sentence naturally implies something like:

• I get ready and check ... before going out
• or one gets ready and checks ... before going out

In many standalone textbook examples, English uses I because it sounds natural, even though Japanese does not explicitly say it.

It breaks down like this:

• 出かける前に = before going out
• 支度して = get ready, and then...
• 忘れ物がないか = whether there is anything forgotten
• 確認します = check

So the overall structure is:

[Before going out] + [do action 1] + [do action 2]

More literally:

Before going out, I get ready and check whether there are any forgotten items.

The comma is mainly there to make the sentence easier to read.

• 支度して、忘れ物がないか確認します。

It shows a slight pause between the connected actions. Japanese commas are often flexible, so this sentence could also be written without one:

• 出かける前に支度して忘れ物がないか確認します。

The meaning does not change much. The version with the comma is just easier to process.

Yes. Normal Japanese writing does not use spaces between words.

The standard written form would be:

出かける前に支度して、忘れ物がないか確認します。

Spaces are often added only in teaching materials to help learners see the parts more clearly.