Ovaj telefon je skup, ali ova knjiga nije skupa.

to be

Breakdown of Ovaj telefon je skup, ali ova knjiga nije skupa.

• ne: not
• ali: but
• knjiga: book

Questions & Answers about Ovaj telefon je skup, ali ova knjiga nije skupa.

Why do we have ovaj with telefon, but ova with knjiga?

Because Serbian words must agree in gender.

• telefon is masculine
• knjiga is feminine

The demonstrative this changes form to match the noun:

• ovaj telefon = this phone
• ova knjiga = this book

So ovaj is the masculine form, and ova is the feminine form.

Why is it skup for telefon, but skupa for knjiga?

For the same reason: adjectives also agree with the noun in gender.

• telefon is masculine, so: telefon je skup
• knjiga is feminine, so: knjiga je skupa

So the adjective skup changes depending on what it describes:

• masculine: skup
• feminine: skupa
• neuter: skupo

Even though the adjective comes after je / nije, it still agrees with the subject.

What does skup mean here exactly?

Here, means .