The nouns that have only plural form are called pluralia tantum. Most of these nouns are made of two parts which make the whole. They require verbs and adjectives in plural. They are either feminine or neuter gender, but used in plural.
Some of them are: makaze, vrata, djeca, jasle, pantalone, farmerice, naočare, novine, merdevine (stube), gaće, leđa, pluća, usta, daire, finansije, fekalije, elektronika, grudi, kola, agrumi, sanke, itd.
In order to determine which gender they belong to, we use the demonstrative pronoun taj, which in plural masculine is ti , plural feminine teand plural neuter ta.
For example: ti agrumi (m.), te sanke (f.), ta vrata (n.)