Júlia prefere assar o frango com alho, mas Ana gosta de fritar cebola no óleo.

Because after verbs like preferir and gostar de, Portuguese often uses another verb in the infinitive.

• Júlia prefere assar o frango = Júlia prefers to roast the chicken.
• Ana gosta de fritar cebola = Ana likes to fry onion.

This works much like English to roast / to fry, except Portuguese usually does not need a separate word like to before the infinitive.

Because the verbs behave differently:

• preferir is followed directly by another verb:
  • prefere assar
• gostar normally requires de:
  • gosta de fritar

So you should learn gostar as gostar de.

Examples:

• Eu gosto de cozinhar.
• Ela gosta de dançar.

But:

• Eu prefiro cozinhar em casa.
• Ela prefere dançar samba.

No is a contraction of:

• em
  • o = no

So:

• no óleo = in the oil / in oil

Portuguese very often contracts em with definite articles:

• em + o = no
• em + a = na
• em + os = nos
• em + as = nas

Examples:

• na panela = in the pan
• no forno = in the oven

Here alho is being used in a general ingredient sense, so Portuguese often leaves out the article.

• com alho = with garlic

This is similar to English, where we usually say with garlic, not with the garlic, unless we mean some specific garlic already mentioned.

If you said com o alho, it would usually sound like a specific garlic already known in the conversation.

Both are possible in Portuguese, and article use with food can vary depending on whether the speaker means something specific or a general ingredient.

• assar o frango often sounds like roasting the chicken / a particular chicken dish.
• fritar cebola often sounds more general, like frying onion as an ingredient.

You may also hear:

• fritar a cebola
• assar frango

Portuguese article use is often more flexible than English, especially with foods and ingredients.

When talking about an ingredient in a general cooking sense, Portuguese often omits the article.

So:

• fritar cebola = to fry onion
• cortar tomate = to cut tomato
• usar alho = to use garlic

But fritar a cebola is also possible if the speaker means a specific onion or is thinking of it as a more definite item in the cooking process.

The written accents show where the stress goes.

• Júlia: stress on JÚ
• óleo: stress on Ó

Approximate pronunciations in Brazilian Portuguese:

• Júlia ≈ ZHOO-lee-a or JOO-lee-a depending on accent
• óleo ≈ OH-lee-oh

A few useful notes:

• The j in Brazilian Portuguese sounds like the s in measure or the zh sound.
• The lh in alho is like the lli in million for many English speakers, though not exactly the same.

In standard written Portuguese, personal names are commonly used without articles:

• Júlia prefere...
• Ana gosta de...

In spoken Brazilian Portuguese, some regions often use articles before names:

• A Júlia prefere...
• A Ana gosta de...

Both patterns exist, but without the article is very normal, especially in writing and in textbook examples.

Yes, in this sentence mas means but and connects two contrasting ideas:

• Júlia prefere assar o frango com alho, mas Ana gosta de fritar cebola no óleo.

So the contrast is:

• Júlia prefers one cooking method
• Ana likes another

It works very similarly to English but.

They are two different cooking verbs:

• assar = to roast, bake, grill (depending on context)
• fritar = to fry

So:

• assar o frango = to roast/bake/grill the chicken
• fritar cebola no óleo = to fry onion in oil

Cooking verbs in Portuguese do not always match English one-to-one, so context matters.

No. The ending -a here is not because Ana is female. It is because gosta is the third-person singular form of the verb gostar.

• eu gosto = I like
• você/ele/ela gosta = you/he/she likes

So:

• Ana gosta
• Júlia prefere

The verb form matches the grammatical person, not the gender of the speaker or subject.

No, that would sound incorrect in standard Portuguese.

With gostar, you normally need de:

• Ana gosta de fritar cebola no óleo.

The same is true with nouns:

• Ana gosta de música.
• Ana gosta de café.

So it is best to memorize the pattern as gostar de.

The sentence follows a very common Portuguese pattern:

• Júlia = subject
• prefere = verb
• assar o frango com alho = complement

Then:

• mas = but
• Ana = subject
• gosta de = verb phrase
• fritar cebola no óleo = complement

So the overall structure is very similar to English:

• Júlia prefers to roast the chicken with garlic, but Ana likes to fry onion in oil.

It can suggest either, depending on context.

• assar o frango com alho usually means the chicken is roasted with garlic as an ingredient or seasoning.

Portuguese often leaves that kind of detail implied. The exact culinary meaning depends on the recipe or situation.

Usually frango refers to chicken as food, especially in a sentence like this.

For the animal, Portuguese more often uses:

• galinha = hen/chicken
• galo = rooster

So in cooking contexts:

• frango almost always means chicken meat or a chicken dish.