tiisai kodomo ha ha wo migakuno wo iyagarukoto ga arimasu.

They are just there to make the sentence easier for learners to read.

In normal Japanese writing, this would usually be written without spaces:

小さい子供は歯を磨くのを嫌がることがあります。

So the spaces are not part of the grammar.

小さい is an i-adjective, and i-adjectives directly modify nouns.

So:

• 小さい子供 = small child / young child

There is no extra word needed between them.

A learner may also wonder about 小さな子供. That is also possible, but 小さい子供 is the more straightforward, regular adjective+noun pattern.

It can mean either, depending on context.

Japanese nouns usually do not change form for singular vs. plural the way English nouns do. So:

• 子供 can mean a child
• 子供 can also mean children

In this sentence, it is being used generically, so in natural English it is often translated as small children.

は marks the topic.

So 小さい子供は means something like:

• As for small children, ...
• Small children, ...

It does not simply mark the subject in the same way English does. It introduces what the sentence is about.

This gives the sentence a general statement feel: it is talking about small children as a group/category.

In Japanese, body parts are often mentioned without a possessive like my, your, or their when the owner is obvious from context.

So:

• 歯を磨く = brush teeth / brush one’s teeth

Japanese does not need to explicitly say their teeth here, because it is understood that the children are brushing their own teeth.

Here, の turns the verb phrase into a noun-like unit.

• 歯を磨く = to brush teeth
• 歯を磨くの = brushing teeth / the act of brushing teeth

This is called nominalizing the verb.

So the sentence is not just talking about the action brush as a verb; it is treating brushing teeth as a thing that can be disliked or resisted.

Because they belong to two different parts of the sentence.

1. 歯を磨く

   • The first を marks 歯 as the object of 磨く.
   • 歯を磨く = brush teeth

2. 歯を磨くのを嫌がる

   • The second を marks the whole nominalized action 歯を磨くの as the object of 嫌がる.
   • 歯を磨くのを嫌がる = to dislike/resist brushing teeth

So the structure is:

• 歯 を 磨く
• [歯を磨くの] を 嫌がる

嫌がる means to act as if one dislikes something, to show reluctance, or to resist.

This is different from:

• 嫌いだ = to be disliked / to dislike
• 嫌だ = unpleasant / I don’t want to

A key point is that 嫌がる is often used for what someone else outwardly shows through their behavior, especially in third person.

So in this sentence, the nuance is not just:

• small children dislike brushing their teeth

but more specifically:

• small children sometimes resist brushing their teeth
• small children sometimes act like they do not want to brush their teeth

That makes 嫌がる very natural here.

They are doing different jobs here.

• の in 歯を磨くの turns brush teeth into brushing teeth
• こと in 嫌がることがあります helps express there are times when... / sometimes...

So:

• 歯を磨くの = the act of brushing teeth
• 嫌がることがあります = there are occasions when they resist/dislike it

In other words:

• の nominalizes the smaller action
• ことがあります packages the larger event as something that sometimes happens

Here, ことがあります means:

• there are times when...
• sometimes...

So:

• 歯を磨くのを嫌がることがあります = there are times when they resist brushing their teeth = they sometimes dislike/resist brushing their teeth

This use of ことがあります expresses occasional occurrence, not a constant habit.

Because こと is not a person or animal. It refers to an event, situation, or occurrence.

Japanese uses:

• ある / あります for things, events, and abstract matters
• いる / います for people and animals

Since 嫌がること means something like the event/occasion of resisting, あります is correct.

Yes.

Because of:

• 小さい子供は as a topic
• ことがあります meaning sometimes

the sentence sounds like a general observation about small children.

So it is more like:

• Small children sometimes resist brushing their teeth

rather than:

• This one particular small child resists brushing their teeth

unless the wider context makes it specific.

Literally, it is small child, but in natural English it often means young child.

That is because when talking about people, small often implies age as well as physical size. So depending on context, 小さい子供 can sound like:

• a small child
• a young child
• small children

In this sentence, young children or small children both work well in English.