Avui la sopa fa bona olor.

Literally, fa bona olor is something like makes a good smell or gives off a good smell.

In Catalan, fer is used in several very common expressions where English uses be, smell, or other verbs. So:

• fa bona olor = smells good
• fa mala olor = smells bad

This is a normal, idiomatic Catalan structure, especially for food, perfume, flowers, etc.

Fa is the 3rd person singular present of fer (to do / to make).

Here it matches la sopa:

• la sopa = singular
• so the verb is fa = it does / it makes

If the subject were plural, the verb would change:

• Les sopes fan bona olor. = The soups smell good.

Because bona agrees with olor, not with sopa.

• olor is feminine singular
• so the adjective must also be feminine singular
• bon → masculine singular
• bona → feminine singular

So:

• bona olor = correct
• bon olor = not correct here

This can feel strange to English speakers, because English adjectives do not change form.

In this expression, Catalan normally says fer bona olor without an article.

So the natural phrase is:

• fa bona olor = smells good

You can sometimes hear:

• fa una bona olor

but that adds a slightly different nuance, more like gives off a really nice smell or has such a nice smell.

So for the basic idea, fa bona olor is the standard, idiomatic version.

Because bona olor is the normal fixed expression.

Although many Catalan adjectives often come after the noun, some very common combinations are more natural with the adjective before the noun, and bona olor is one of them.

So:

• bona olor = natural
• olor bona = not the usual way to say it here

It is best to learn bona olor as a chunk.

Putting avui first is a very natural way to set the time frame: today.

So the sentence structure is basically:

• Avui = today
• la sopa = the soup
• fa bona olor = smells good

Catalan word order is fairly flexible, so other orders are possible too, such as:

• La sopa avui fa bona olor.

But Avui at the beginning is very natural if the speaker wants to highlight today.

Because sopa is a feminine singular noun, so it takes the feminine singular definite article la.

• la sopa = the soup

Catalan often uses the definite article in places where English may also use the, but sometimes Catalan uses articles a bit more readily than English does. In this sentence, la sopa refers to a specific soup already known in the context.

Fer bona olor is a very normal and idiomatic way to say that something smells good.

You may also hear olora bé, which can also mean it smells good. But fer bona olor is especially common for describing the smell something gives off.

For example:

• La sopa fa bona olor.
• La sopa olora bé.

Both can work, but fa bona olor is a very safe and natural phrase to learn.

It is also helpful because olorar can mean both to smell and to sniff/smell something, so fer bona olor is very clear.

You just put no before the verb:

• Avui la sopa no fa bona olor. = Today the soup doesn’t smell good.

This is the normal way to negate Catalan sentences.

In Catalan, you usually keep the same word order and use intonation when speaking, or a question mark in writing:

• Avui la sopa fa bona olor? = Does the soup smell good today?

So unlike English, you do not normally need to add a helping verb like does.

Catalan simply uses the statement form as a question, with questioning intonation.