бити / бивати + Passive Participle

In standard Serbian, the periphrastic passive operates differently from English. English uses 'to be' + participle for both states and active ongoing events ('The window is broken' vs. 'The road is being paved'). Serbian strictly separates these functions:

1. Stative Passive with бити / јесам (Пасив стања)
When you combine the enclitic present tense of the auxiliary јесам (functionally treated alongside бити: сам, си, је, смо, сте, су) with a passive participle (трпни глаголски придев), it typically describes an existing state or result in the present:

• Сви рачуни су плаћени. (All bills are paid / settled.)
• Продавница је затворена. (The shop is closed.)

Note that standard morphological grammars classify сам, си, је... as forms of јесам (contrasting with the perfective present будем, будеш... of бити). This periphrastic combination has a dual syntactic role in Serbian: it can represent either a present state (пасив стања, e.g., 'The shop is currently closed') or a passive past action / passive perfect (пасивни перфекат, e.g., 'The shop was closed [yesterday]'). It does not function as an active past tense (перфекат), which strictly requires the active participle (радни глаголски придев, e.g., затворила је). Context clarifies whether a present result or a past passive event is intended.

2. Iterative Passive with бивати (Пасив радње са понављањем)
Serbian standard grammar resists using јесам/бити in the present to describe ongoing passive actions. Instead, the imperfective frequentative verb бивати (бивам, биваш, бива, бивамо, бивате, бивају) is paired with a participle to denote actions that recur regularly or habitually across intervals:

• Најбољи ученици бивају награђени. (The best students routinely get rewarded.)

This construction belongs predominantly to administrative, legal, and formal registers. In everyday speech, native speakers prefer active verbs or reflexive constructions.

3. The Reflexive Passive Alternative
To describe a single, dynamic passive process happening right now (English 'is being done'), Serbian does not use present јесам/бити or бивати. Instead, it uses the reflexive construction (се пасив):

• Мост се тренутно гради. (The bridge is currently being built — NOT: *Мост је тренутно грађен).

Note that Мост је грађен is not inherently ungrammatical; it represents a past imperfective passive process ('The bridge was being built [at that time] / was under construction'), but it cannot express an ongoing present event.

4. Expression of Agency and Causes
In genuine Serbian prose, explicit human agents introduced by од стране + genitive ('by...') are considered clumsy administrative calques; when a human agent is known and relevant, speakers recast the clause in the active voice. However, standard Serbian routinely and naturally expresses inanimate causes, natural forces, and instruments using the bare инструментал:

• Град је погођен земљотресом. (The city was struck by an earthquake.)
• Кућа је покривена снегом. (The house is covered with snow.)