gomi wo bunbetusimasu.

Because ごみ is very often written in hiragana in everyday Japanese.

A few things to know:

• The kanji form is ゴミ in katakana or sometimes 塵 in kanji, but 塵 is rare in normal modern writing.
• In signs, apps, and daily writing, you will commonly see:
  • ごみ
  • ゴミ
• ごみ in hiragana feels very normal and easy to read.

So even if a word has a possible kanji-related form, Japanese often prefers hiragana or katakana for common everyday words like this.

を marks the direct object of the verb.

In ごみ を 分別します, the thing being sorted is ごみ.

So:

• ごみ = garbage / trash
• を = marks garbage as the object
• 分別します = sort / separate

A natural breakdown is:

• ごみを = the garbage (as the thing being acted on)
• 分別します = sort it

In modern Japanese, を is pronounced o.

So this sentence is pronounced roughly:

gomi o bunbetsu shimasu

Even though it is written を, you usually do not pronounce it as wo in normal modern speech.

You may still see it romanized as wo sometimes, mainly to show that it is the particle を, but the actual pronunciation is basically o.

分別します is the polite form of the verb 分別する.

This is a suru-verb:

• 分別 = separation / sorting into categories
• する = to do

Together:

• 分別する = to sort, separate, classify

Then the polite form is:

• 分別します = sort / will sort / do sorting

This pattern is very common in Japanese:

• 勉強する = to study
• 掃除する = to clean
• 分別する = to sort

します is the polite non-past form of する.

Compare:

• 分別する = plain form
• 分別します = polite form

Japanese often uses the polite -ます form in:

• everyday conversation with people you are not close to
• workplace language
• instructions
• signs and notices
• textbook example sentences

Also, します is called non-past, which means it can refer to:

• a habitual action: I sort the trash
• a future action: I will sort the trash

The exact time usually comes from context.

The subject is omitted, which is very normal in Japanese.

Japanese often leaves out words like:

• I
• you
• we
• they

if the meaning is clear from context.

So ごみを分別します could mean:

• I sort the trash
• We sort the trash
• Please sort the trash (in some contexts, though this sentence by itself is more like a statement)
• They sort the trash

Japanese does this much more often than English, so this is something learners get used to over time.

It can be translated as either, depending on context.

With ごみ, 分別する usually means something like:

• sort the trash
• separate the trash
• separate garbage into categories

For example, this often means separating things like:

• burnable trash
• plastic
• cans
• bottles
• paper

So sort is often the most natural English translation, but separate is also correct.

Yes, 分別する is a very common word for sorting trash into categories.

It sounds a bit more specific than just 分ける.

For example:

• 分ける = divide, separate, split
• 分別する = sort/classify into proper categories

So for garbage rules, recycling instructions, or city notices, 分別する is a very natural choice.

No, normal Japanese writing usually does not use spaces between words.

So in ordinary writing, this would usually appear as:

ごみを分別します。

Spaces are often added in learning materials to help beginners see where one part ends and the next begins.

That is why you may see:

• ごみ　を　分別します。

in textbooks or beginner exercises, even though that is not standard everyday formatting.

Yes. ごみ and ゴミ are both very common.

Very roughly:

• ごみ feels soft and common in beginner materials and general writing
• ゴミ is also extremely common, especially in signs, labels, and practical everyday contexts

So you might see:

• ごみを分別してください
• ゴミを分別してください

Both are normal.

The basic order is:

object + を + verb

So:

• ごみ = object
• を = object marker
• 分別します = verb

Japanese sentences often put the verb at the end.

That is one of the biggest differences from English.

English:

• I sort the trash.

Japanese:

• (I) trash sort.

Of course, that is just a literal breakdown to show the structure. The natural English translation would still be I sort the trash or We sort the trash, depending on context.