With some dependent clauses introduced by a relative pronoun it is necessary to decide whether the given clause is a relative or content clause. This situation arises especially in the following two cases:
the dependent clause potentially modifies the pronoun ten: this pronoun is either a supporting expression and the dependent clause is a content clause, or else, ten stands in place of a noun and the dependent clause is a relative clause. Cf.:
Přemýšlel o tom, kdo přijde. (=lit. (He) thought about that who is_coming)
= He thought about the person who was coming.
In this case, the dependent clause is a relative clause.
= He was thinking about (the question) whether this one or that one was coming).
With this interpretation, the dependent clause is a content clause.
For more on the competition between content and relative clauses potentially modifying ten, see Section 5.3.1, "Correlative pairs with the supporting expression "ten"".
the dependent clause modifies a noun and either stands in the position of one of its valency modifications (content clause) or it just says something about the noun (specifies a quality/property; relative clause).
If a dependent clause introduced by a relative pronoun modifies a noun with valency requirements, we use the definitions of content and relative clauses in Section 5, "Dependent verbal clauses" to determine which type we are dealing with in the particular case: content clauses occupy the position of one of the noun's arguments; relative clauses only further specify the noun. Cf.:
Otázka, která nebyla položena.RSTR, nemůže být zodpovězena. (=The question which wasn't asked cannot be answered)
The dependent clause is a relative clause.
Otázka, která malba je.PAT nejvydařenější, nemůže být zodpovězena. (=The question which painting is the best cannot be answered)
The dependent clause is a content clause.
Informace, které jsme získali.RSTR, nám nepomohly. (=The information we got didn't help us)
The dependent clause is a relative clause.
Informace, které úvěry jsou.PAT výhodné, nám nepomohly. (=The information which bank loans are better didn't help us)
The dependent clause is a content clause.
In unclear cases, the knowledge of the context is decisive. Cf.:
Informace, která je.RSTR nejdůležitější, nesmí být zapomenuta. (=lit. Information which is the_most_important mustn't be forgotten)
= The most important information must not be forgotten.
With this interpretation, the dependent clause is a relative clause.
Informace, která je.PAT nejdůležitější, nesmí být zapomenuta.
= The information which thing is the most important must not be forgotten.
With this interpretation, the dependent clause is a content clause.
For the consequences of distinguishing content from relative clauses for the pronouns "který" and "jaký" see Section 1.2, "Pronouns in the role of a syntactic adjective or noun".
The connective co is used with content, relative as well as adverbial clauses.
Distinguishing content and relative clauses with the connective co follows the rules in the first paragraphs of Section 5, "Dependent verbal clauses" and Section 5.2, "Content vs. relative clauses". It is not possible to use the information regarding the part-of-speech character of the connective. Co can be either considered a subordinating conjunction or relative pronoun. If co is a modification of the dependent clause main verb, it is a relative pronoun; if not, it is a subordinating conjunction.
"Co" introducing an adverbial clause If co introduces an adverbial clause, it is considered a subordinating conjunction.
For example:
<Co> odešli.TSIN , je tu klid. (=Since they left, it's been so calm here)
"Co" introducing a relative clause If co introduces a relative clause, it can belong to two different part-of-speech categories:
it is a relative element.
Co is a relative pronoun if it corefers with the noun the dependent clause modifies. There is a grammatical coreference relation between co and the noun in the governing clause (marked in the tree).
Examples:
Mluvil o těch, co.ACT přišli.RSTR (=He was talking about those who came)
Dostal jsem knihu, co.PAT jsem už četl.RSTR (=I got a book which I had read before)
Člověk, co.ACT kráčí.RSTR po chodníku, je můj známý. (=The man who is walking on the pavement is someone I know)
Žena, co.PAT potkal.RSTR na schodech, nosí krátké sukně. (=The woman he met on the stairs wears short skirts)
V okamžiku, co.TWHEN jsem ho spatřil.RSTR , upadl na zem. (=At the very moment I saw him he fell on the ground)
co is a subordinating conjunction.
Co is a subordinating conjunction in those relative clauses in which there is a pronoun coreferring with the modified noun in the dependent clause (in the appropriate form). Co is, then, not a modification of the verb but it rather just connects the clauses (and is not assigned a separate node, just like other subordinating conjunctions). The relative clause is introduced by a subordinating conjunction in this case, despite the definition of relative clauses in Section 5, "Dependent verbal clauses"!
Examples:
Ten kluk, <co> ho.PAT Jirka potkal.RSTR , bydlí v naší ulici. (=lit. That boy what/that him Jirka met lives in our street)
Dostal jsem knihu, <co> jsem ji.PAT už četl.RSTR (=lit. (I) got book what/that (I) have it already read)
Schránku, <co> do ní.PAT hodil.RSTR dopis, už vybrali. (=lit. Post-box.ACC what/that into it (he) threw letter (they) already emptied)
Žena, <co> ji.PAT potkal.RSTR na schodech, nosí krátké sukně. (=lit. Woman what/that (he) her met on stairs wears short skirts)
"Co" introducing a content clause. Co introducing content clauses is always a relative pronoun; it is always a modification (of the verb) in the dependent clause.
Examples:
Přemýšlela, co.PAT si vezme.PAT na sebe. (=She was thinking about what she was going to wear)
Neuměla vysvětlit, co.PAT udělala.PAT (=She couldn't explain what she did)
NB! With content clauses, co often combines with the suppporting pronoun ten (see Section 5.3.1, "Correlative pairs with the supporting expression "ten""), e.g.:
Přemýšlela <o tom>, co.PAT si vezme.PAT na sebe. (=lit. (She) was_thinking about that what (she) is_going_to_wear --)
Neuměla vysvětlit <to>, co.PAT udělala.PAT (=lit. (She) couldn't explain that what (she) did)
NB! Ten preceding a content clause is to be distinguished from ten substituting the noun modified by a relative clause (see also Section 5.3.1, "Correlative pairs with the supporting expression "ten""). Cf.:
Mluvil o těch.PAT, co.ACT přišli.RSTR (=He talked about those who came)
Ten stands for the noun modified by a relative clause. The effective root node of the relative clause depends on ten.
Neuměla vysvětlit <to>, co.PATudělala.PAT (=She wasn't able to explain what (lit. that what) she had done)
The pronoun ten is a supporting expression and the dependent clause is a content clause (its effective root node depends on the main verb of the governing clause).