Let’s learn how to talk about anything else in Croatian. For instance, something has happened, for instance Ana has bought a car. Now, you know it, and you want to tell that fact. In English, you would say:
I know (that) Ana has bought a car.
In English, you simply add that + what you know, and the word that is usually left out. In Croatian, you must use the word da:
Znam da je Ana kupila auto.
The word da holds the first position in the clause, as usual, so all second-position words (here just je) come right after it:
Znam [da je² Ana kupila auto].
Such clauses that can hold any information, but follow the same rules as normal sentences, are called content clauses.
The most common verbs used with such clauses are (by descending order of certainty):
vjerovati (vjeruje) believe
Out of those verbs, znati and misliti are most used in spoken language. The verb vjerovati (vjeruje) believe is mostly used in negative:
Ne vjerujem da je Ana kupila auto. I don’t believe Ana has bought a car.
Such clauses can be used by verbs of information transfer (really, verb pairs). All of them allow for an optional recipient of information expressed in DL and a content clause (or an object in A):
čitati ~ pro- read
dokazivati (dokazuje) ~ dokazati (dokaže) prove
javljati ~ javiti inform, let know
govoriti («) ~ reći (reče, rekao, rekla) tell, say
objašnjavati («) ~ objasniti («) explain
pisati (piše) ~ na- («) write
pokazivati (pokazuje) ~ pokazati (pokaže) show
priznavati (priznaje) ~ priznati admit
Objasnila je Ani da uči hrvatski. She explained to Ana that she has been learning Croatian.
The present tense forms of reći (...) are rare: the verb kazati (kaže) is used instead. This verb is also sometimes used in the true present tense, as an imperfective verb:
Kažem ti da nisam gladna. I’m telling you I’m not hungry.
You can talk about what someone said (reported speech). For instance, someone said:
„Učim hrvatski.” “I’m learning Croatian.”
To report about it, you should (as in English) change it to the 3rd person, since you’re talking about someone else (here I assume that that person is female, but the Croatian sentence is here completely unspecific, since it’s in the present tense):
Kaže da uči hrvatski. She says she’s learning Croatian.
Znam da će padati kiša. I know it's going to rain.
However, if you report about the past, in English the reported clause gets time-shifted, e.g.:
She said she was learning Croatian.
I knew it was going to rain.
There’s no time-shift in Croatian. We simply report things in the original tense (that’s one more thing where Croatian is simpler than English):
Rekla je da uči hrvatski.
Znala sam da će padati kiša.
Therefore, we literally say ‘I knew it will rain’.
Croatian content clauses are not rearranged normal sentences, only a da is put to the front. There’s no replacement of biti with (bude), perfective verbs cannot be used in the present tense unless the verbs can be used in normal sentences, etc. This behavior is completely different from superficially similar desire or purpose clauses, which also start with da.
Next, you can use any information in your sentence. For example, where the car is:
Gdje je auto? Where is the car?
Znam [gdje je auto]. I know where the car is.
Pay attention how English is holds different positions in the question and the I-know sentence. This doesn’t happen in Croatian, there’s no rearrangement whatsoever. (You cannot use any other arrangement, as the question-word, here gdje, must start both a question and a derived clause).
Questions are simply re-used as clauses, now da must not be used, since you already have a "connecting" word to start the clause. The following examples are a "what" and an "opinion" clause:
Što si rekao? What did you say?
Čula sam što si rekao. I heard what you said.
Što da radim? What should I do?
Ne znam što da radim. I don’t know what I should do. (or what to do)
I sometimes make mistakes in English, keeping the question word order – my native language has no rearrangement. You can use questions for reasons, time, etc.:
Ne znam [zašto je otišla]. I don't know why she left.
Next, you can express that you don’t know if something is true or not (or you’re trying to find out, or you’re interested in, etc.). In Croatian, you simply use yes/no questions as clauses:
Je li kupila auto? Did she buy a car?
Ne znam [je li kupila auto]. I don’t know if she bought a car.
Again, the English sentence must be rearranged – from a question to a report – but Croatian is not rearranged. You simply use questions as clauses!
However, you cannot use shortened forms of questions. In the following examples, shortened questions (1) cannot be used as clauses, only the full forms (2):
1 Da li da kupim auto? Should I buy a car?
2 Da kupim auto? (the same, but shortened)
Ne znam [da li da kupim auto]. I don’t know if I should buy a car.
This applies to colloquial forms as well:
1 Jel idemo u kino? (colloq.) Are we going to cinema?
2 Idemo u kino? (the same, but shortened)
Zanima me [jel idemo u kino]. (colloq.) I wonder if we’re going to cinema.
Besides znati know, and two verbs vidjeti (...) see and čuti (čuje) hear, introduced long ago, there are following common verbs of knowledge and perception:
osjećati ~¹ osjetiti (+ A/CC) feel
primjećivati (primjećuje) ~¹ prim
ijetiti («) (+ A/CC) notice
razumjeti (razumije,...) (+ A/CC) understand
shvaćati® ~~ shvatiti (+ A/CC) understand
You have likely noticed some special notation in the verb pair list (~¹, ~~). Actually, the perf. verbs in such pairs are not ordinary perf. verbs. They rather indicate start of state or a single instance. Therefore, osjetiti means feel for a moment, while shvatiti indicates the moment you understood something – it’s implied you understand it from then on. Such verbs are explained in detail in 81 Sneeze Once and Start Blooming.
As with znati know, these verbs are used either with objects in A or content clauses:
ijetila je da nema Ane. She noticed that Ana wasn't there.
Osjećam da će padati kiša. I feel it's going to rain.
Razumijem da nemaš puno vremena. I understand you don't have much time.
You can talk about content clauses, making them really subjects. As they are not nouns, they behave as if neuter singular, as you can see from the past tense:
Dobro je [da ne pada kiša]. It’s good it’s not raining.
Bilo je dobro [da nije padala kiša]. It was good it wasn’t raining.
The second clause is in the past tense: we’re not reporting what somebody else said, but what was. There are a lot of similar ways to comment content, e.g. with the following words instead of dobro:
šteta too bad
You can use many other adjectives to comment on content, including colloquial super great and more. You can add also who thinks/feels that in DL:
Ani je jasno da... It’s clear to Ana that...
Ani je bilo jasno da... It was clear to Ana that...
There’s one special rule – if you just comment (without who feels/thinks in DL) in the present tense, you can leave je² out (I’m not completely sure if that’s accepted in standard or not, but it’s quite widespread):
Dobro da ne pada kiša. It’s good it’s not raining.
There are two very common and similar expressions, with stronger meaning than dobro da...:
sva sreća da...
The expression sva sreća da... is especially common to express that something might have been much worse (e.g. a building collapsed, but, fortunately, nobody was in it at that moment):
Sva sreća da ne pada kiša. Fortunately, it’s not raining.
You can express feelings with dative phrases involving drago and žao:
Ani je žao da... Ana was sorry that...
Ani je bilo drago da... Ana was glad/happy that...
You can like content (here content clauses are again subjects):
Sviđa mi se da je Ana došla. I like that Ana came.
You can also hope for something, then the content clause is an object:
Nadam se da je Ana došla. I hope Ana came.
You can also refer to the content expressed before using the general pronoun to. That’s often used in conversation, but also common in writing:
Ana je kupila auto. Ana bought a car.
— Nisam to znao. I didn’t know that.
You can use to and a content clause anywhere, even after prepositions (you have to change to into the right case):
Razgovarali smo o tome da je Ana kupila auto. We discussed about Ana buying a car. (lit. ‘about that Ana has bought a car’)
If you comment on a known fact, you can use što instead of da – it doesn’t change when in this role:
Dobro je što ne pada kiša. It’s good it’s not raining.
Finally, you can remember some event, forget to do something, then you can expect or fear that something might happen, etc.; I will explain all such uses in 69 Memories, Expectations and Fear.