Knjiga koju sada čitam je dobra.

to be

Breakdown of Knjiga koju sada čitam je dobra.

• dobar: good
• sada: now
• knjiga: book

Questions & Answers about Knjiga koju sada čitam je dobra.

Why is it koju and not koja?

Because koji is a relative pronoun, and it changes form.

Here is what controls it:

• gender and number come from knjiga → feminine singular
• case comes from its role inside the relative clause

In koju sada čitam, the book is the direct object of čitam (I am reading), so Serbian uses the accusative feminine singular form:

• nominative: koja
• accusative: koju

So knjiga koju čitam is literally the book which I am reading.

What case is knjiga in?

Knjiga is in the nominative singular because it is the subject of the main clause.

The main clause is:

• Knjiga ... je dobra.

So:

• knjiga = subject
• je dobra = predicate

Even though the sentence also contains a relative clause, the noun knjiga itself is still the subject of the whole sentence.

Why is čitam used here? Does it mean I read or I am reading?

In Serbian, the present tense often covers both meanings that English separates into: