Learn Hardcore Croatian: U kabini sam vidjela da su hlače preduge, pa sam odmah pitala za zamjenu. - In the fitting room I saw that the pants are too long, so I immediately asked for an exchange.

In Croatian, short unstressed words (clitics) like sam usually go in the “second position” of the clause—after the first stressed element. Here the sentence starts with U kabini, so the clitic sam comes right after it: U kabini sam vidjela...
You can also say Vidjela sam... if the clause starts with the verb, but U kabini vidjela sam... is generally not preferred.

What does sam vidjela mean grammatically—what tense is it?

It’s the Croatian past tense (often called the perfect):

sam = present of biti (to be) used as an auxiliary (I am)
vidjela = past active participle (seen)
Together: sam vidjela = I saw / I have seen (context decides which English translation fits better).

Why does the verb form vidjela end in -a?

Because the speaker is grammatically feminine. Past participles agree with the subject’s gender and number:

masculine: vidio sam (I saw)
feminine: vidjela sam
neuter is rare for people, but exists in grammar.

Why isn’t the subject pronoun ja (I) included?

Croatian is a pro-drop language: the verb/auxiliary already shows the person, so ja is usually unnecessary. You’d add ja only for emphasis or contrast (like “I (not someone else) saw…”).

Why does Croatian use da here: vidjela da su...?

After verbs of seeing/knowing/saying, Croatian commonly introduces an embedded statement with da (roughly “that”):

Vidjela sam da su hlače preduge = “I saw that the pants were too long.”
You can sometimes omit “that” in English, but da is normally required in Croatian.

Why is it su and not je in da su hlače...?

Because hlače is grammatically plural, so the auxiliary in the embedded clause must be plural:

je = he/she/it is
su = they are
So: hlače su preduge = “the pants are too long.”

Why are hlače plural—can you say it as singular?

In Croatian, hlače (trousers/pants) is a plural-only noun (like “scissors” in English). You normally treat it as plural in agreement: hlače su, preduge.
If you want a singular item-word, you might use something like par hlača (a pair of pants), but everyday speech usually just uses hlače as plural.

Why is preduge plural feminine—how does it agree?

Predicate adjectives agree with the noun in gender/number/case. Here:

hlače = plural, and grammatically feminine plural
So the adjective is feminine plural: preduge (“too long”).
(For comparison: kaput je predugačak could be masculine singular “the coat is too long”.)

Why does u kabini use u + locative, and what would u kabinu mean?

u + locative is used for location (“in”): u kabini = “in the fitting room/cubicle.”
u + accusative is used for motion/direction (“into”): u kabinu = “into the fitting room.”
So the sentence uses locative because it describes where the speaker was when she noticed it.

What is the function of pa in the middle of the sentence?

pa is a common connector meaning “so / and then / therefore,” often used in conversational narration to show the next consequence:
...preduge, pa sam odmah pitala... = “...too long, so I immediately asked...”

Why is sam repeated: sam vidjela ... pa sam pitala?

Each clause needs its own auxiliary in the past tense. Croatian doesn’t usually “carry over” sam to the next clause the way English can sometimes avoid repeating “I”:

clause 1: (ja) sam vidjela
clause 2: (ja) sam pitala
The subject is the same, but the grammar of each past-tense verb still requires its auxiliary.

Why is it pitala za zamjenu—what does za mean here?

pitati za + accusative means “to ask for” something (request it):

pitala za zamjenu = “asked for an exchange/replacement.”
The preposition za governs the accusative, and zamjenu is the accusative form of zamjena.

What’s the difference between zamjena and something like povrat?

zamjena = an exchange/replacement (swap item for another)
povrat = a return/refund (giving the item back; often money back)
So the sentence specifically says she asked to exchange/replace the pants, not necessarily to return them for a refund.

Does odmah always mean “immediately,” and where can it go in the sentence?

odmah means “immediately/right away.” It’s fairly flexible in position, but typically sits near the verb it modifies:

pa sam odmah pitala... (very natural)
pa sam pitala odmah... (possible, slightly different emphasis)
Putting it earlier generally emphasizes the quickness of the action.