asagohan ni pan wo taberu toki, watasi ha bataa yori zyamu no hou wo yoku tukaimasu.

Here, に marks the occasion or mealtime: for breakfast / at breakfast.

So 朝ご飯にパンを食べる means eat bread for breakfast.

This に is common with meals:

• 朝ご飯にパンを食べます = I eat bread for breakfast.
• 昼ご飯にうどんを食べます = I eat udon for lunch.

It is not the destination に here.

Because the part before とき is a clause modifying a noun, and Japanese uses the plain form before nouns.

• とき means time / when
• パンを食べるとき literally means the time when I eat bread

So:

• 食べるとき = when I eat
• not 食べますとき

This is the same pattern as:

• 日本へ行くとき = when I go to Japan
• 忙しいとき = when I’m busy

食べるとき is used because this sentence talks about a habitual situation: whenever the speaker eats bread for breakfast.

In general:

• Vる とき = when doing / when about to do / whenever one does
• Vた とき = when one did / after doing

So here:

• パンを食べるとき = when I eat bread
• パンを食べたとき would sound more like when I ate bread or after I had eaten bread, depending on context

For a general habit, 食べるとき is the natural choice.

Yes, it could be omitted.

Japanese often leaves out the subject or topic when it is clear from context. So this sentence could naturally be:

• 朝ご飯にパンを食べるとき、バターよりジャムのほうをよく使います。

Adding 私は makes the speaker explicit. It can add:

• clarity
• a slight contrast, like as for me
• a more complete feel in isolation

So it is not required, but it is perfectly natural.

This is a standard comparison pattern:

• A より B のほう = B more than A / B rather than A

So:

• バターよりジャムのほう = jam rather than butter / jam more than butter

The word より marks the thing being compared against:

• バターより = than butter

And のほう means something like the side/option of:

• ジャムのほう = the jam side / the jam option

So the sentence is saying that, between butter and jam, the speaker uses jam more often.

Literally, ほう means side, direction, or one of the options.

In comparisons, it does not mean side literally in English. Instead, it helps express which one is preferred, used more, bigger, better, and so on.

Examples:

• ジャムのほうが好きです = I like jam better.
• こっちのほうが安いです = This one is cheaper.

So in this sentence, ジャムのほう means the jam option or jam rather than butter.

Good question. The particle depends on the role that phrase plays in the sentence.

Here, ジャムのほう is the direct object of 使います:

• ジャムのほうを使います = use jam rather than butter

That is why it takes を.

You often see が in comparison sentences when the compared item is the subject of an adjective or stative expression:

• ジャムのほうが好きです = I like jam better.
• こちらのほうが便利です = This one is more convenient.

But with 使う, the thing used is the object, so:

• ジャムのほうをよく使います

Here, よく means often or frequently.

So:

• ジャムのほうをよく使います = I often use jam / I use jam more often

Be careful: よく can also mean well, depending on context.

Examples:

• 日本語をよく話します can mean speaks Japanese well
• よく行きます = often go

In this sentence, because it is about frequency of using butter or jam, よく clearly means often.

Because the speaker is talking about which spread they use on the bread.

In English, we might say:

• I use jam
• I put jam on my bread
• I have jam with my bread

Japanese often uses 使う naturally for choosing or using a condiment/spread.

Other possible verbs are:

• つける = put on / spread on
• ぬる = spread on

For example:

• パンにジャムをつけます
• パンにジャムをぬります

If you said ジャムを食べます, it would focus more on eating the jam itself, not on using it as the topping of choice.

The overall structure is natural, but Japanese word order is somewhat flexible.

This sentence is organized as:

1. when clause: 朝ご飯にパンを食べるとき
2. topic: 私は
3. comparison + object: バターよりジャムのほうを
4. adverb + verb: よく使います

That is very standard.

You could also say things like:

• パンを朝ご飯に食べるとき、私はバターよりジャムのほうをよく使います。
• 朝ご飯にパンを食べるときは、バターよりジャムのほうをよく使います。

These are similar, though the original sounds smooth and natural.

In this sentence, 朝ご飯に goes with the whole action パンを食べる, meaning eat bread for breakfast.

So the structure is:

• 朝ご飯に = for breakfast
• パンを食べる = eat bread

Together:

• 朝ご飯にパンを食べる = eat bread for breakfast

Japanese often relies on particle relationships rather than strict word order:

• に attaches to 朝ご飯
• を attaches to パン

That tells you what each noun is doing in the sentence.

Yes, it could.

• パンを食べるとき、 simply means when I eat bread
• パンを食べるときは、 adds a stronger topic/contrast feeling, like when it comes to times when I eat bread...

So:

• 朝ご飯にパンを食べるとき、 = when I eat bread for breakfast
• 朝ご飯にパンを食べるときは、 = as for when I eat bread for breakfast

Both are natural. The version without は is a little more neutral and straightforward.