imouto ha tamago ni ketyappu wo kakemasu ga, titi ha soosu no hou ga suki desu.

は marks the topic of each part of the sentence.

• 妹は = As for my younger sister...
• 父は = As for my father...

Here, は helps set up a contrast between the two people:

• the younger sister does one thing
• the father prefers something else

So the sentence is not just giving two facts; it is comparing/contrasting them.

With かけます when it means to pour/sprinkle/put something onto something, Japanese often uses this pattern:

• A に B を かける
• put/pour B onto A

So here:

• 卵に = onto the egg
• ケチャップを = ketchup
• かけます = puts/pours on

So 卵にケチャップをかけます literally works like:

• puts ketchup onto eggs

The particle に marks the target/surface receiving the action.

Because を marks the thing being directly acted on in this expression.

In 卵にケチャップをかけます:

• 卵に = onto the egg
• ケチャップを = the ketchup being applied

So を marks what is being poured/applied, while に marks where it goes.

Here, が means but.

So:

• 妹は卵にケチャップをかけますが、父は...
• My younger sister puts ketchup on eggs, but my father...

This が connects two clauses and shows contrast.

Important: this is a different use of が from the subject-marking particle in phrases like ソースのほうが好きです. Japanese has more than one が, and the meaning depends on where it appears in the sentence.

～のほう often means the ... side, ... rather, or ... more (in comparison).

So ソースのほうが好きです means something like:

• (He) likes sauce better
• (He) prefers sauce
• literally: the sauce side is more liked

The comparison is understood from context. Since the first half mentions ketchup, the idea is:

• the younger sister uses ketchup, but the father prefers sauce

So のほう adds a sense of comparison/choice between alternatives.

Because 好き does not work like a normal verb such as eat or drink.

好き is basically an adjective-like word meaning liked / likable / fond. Because of that, the thing that is liked is usually marked with が, not を.

So:

• ソースが好きです = likes sauce
• ソースのほうが好きです = likes sauce better / prefers sauce

Using を好きです is not the standard pattern here.

This が is the subject marker.

In this part:

• ソースのほうが = sauce, rather / the sauce option
• 好きです = is liked / is preferred

So the thing being preferred is marked by が.

This is different from the earlier が after かけます, which means but. They look the same, but they do different jobs.

Usually, yes. ～のほうが好きです strongly suggests choosing one thing over another.

Sometimes the other option is stated:

• 猫より犬のほうが好きです
• I like dogs more than cats

Sometimes the other option is only understood from context, like in your sentence:

• younger sister: ketchup
• father: sauce instead / sauce more

So here the comparison target is implicitly ketchup.

Japanese nouns usually do not show singular vs. plural the way English does.

So 卵 can mean:

• egg
• eggs

You understand the number from context. In a sentence like this, English might translate it as eggs because that sounds more natural, but the Japanese itself does not force that distinction.

In a sentence like this, 父 usually means my father.

Japanese often omits words like my when the relationship is obvious from context. The same goes for 妹, which usually means my younger sister here.

So:

• 妹 = my younger sister
• 父 = my father

This is very natural in Japanese.

When speaking about your own family members to other people, Japanese often uses the plain family terms:

• 父 = my father
• 母 = my mother
• 妹 = my younger sister

Forms like お父さん are often used when:

• directly addressing your father
• talking about someone else’s father
• speaking in a warmer or more familiar style in some contexts

So 父 fits well here because the speaker is simply talking about his or her own father.

Yes, in everyday conversation, けど would be very natural:

• 妹は卵にケチャップをかけますけど、父はソースのほうが好きです。

Both mean but, though there can be slight differences in tone. が can sound a bit more neutral or written, while けど often sounds more conversational.

In this sentence, either works grammatically.

Not exactly. In Japanese, 好き is better understood as an adjective-like predicate rather than a normal action verb.

That is why the structure feels different from English:

• English: Father likes sauce
• Japanese: As for father, sauce is liked / preferred

You do not need to translate it literally every time, but understanding this helps explain why Japanese uses が with 好き.