bị

Structure:
Subject (Victim/Object) + bị + (Agent) + Verb + (Object)
Subject + bị + Adjective / Noun

Key Rules:

• No verb changes: Because Verbs Never Change Form, you just use the base dictionary word after bị. There is no equivalent to an English "past participle".
• The Subject (People vs. Things): In Vietnamese, the subject can be the person who suffers the loss (the "Experiencer") or the inanimate object itself. If someone steals your bike, you can say Tôi bị kẻ trộm lấy xe đạp (literally: I suffered the thief taking the bike), where the original object remains after the verb. However, you can also make the inanimate object the subject: Xe đạp của tôi bị lấy (My bike was taken). Inanimate objects also take bị when they undergo damage or a negative change (e.g., Cửa sổ bị vỡ - The window is broken, Điện thoại bị hỏng - The phone is broken).
• Agent placement: The person causing the event (the "Agent") is optional. If included, place them directly after bị and before the verb. While formal writing may use By (Agent Phrase), the direct structure is most natural for daily use.
• Negation: To make the sentence negative, place the negative word before bị, not before the verb (e.g., không bị, chưa bị).
• Active, Intransitive, and Situational uses: bị isn't always a passive marker. With nouns or adjectives, it acts as an active verb meaning "to suffer from" (like an illness, e.g., bị cảm - to have a cold). With intransitive verbs, it shows the subject accidentally did something unfortunate to themselves (e.g., Tôi bị ngã - I fell). It is also the core verb used for getting caught in annoying environmental situations (e.g., bị kẹt xe - to be stuck in traffic, bị mắc mưa - to get caught in the rain).
• The 'người ta' workaround: Vietnamese strongly prefers the active voice. Instead of a passive structure, it is very common to use the impersonal pronoun người ta (they/people) as a dummy subject (e.g., Người ta lấy xe đạp của tôi - Someone took my bicycle).

Important Distinctions:
While English often uses "to be + past participle" for passive events, the English "get-passive" (like "get fired" or "get sick") is a much closer equivalent to how Vietnamese works. Vietnamese forces you to choose based on the outcome:

• WARNING: Never use bị for positive events. If you translate "I was promoted" as Tôi bị thăng chức, it sounds like "I suffered a promotion".
• For negative or unwelcome events, use bị.
• For positive or beneficial events, use Passive For Something Welcome.
• For neutral or objective facts, you can use được (e.g., Hội nghị được tổ chức - The conference was organized), use the Zero Passive (no marker at all), or use an active sentence with người ta.