Bei Sentences

Bei Sentences (被字句) are a key way to express the passive in modern Mandarin Chinese. In passive sentences, the object of an action becomes the subject of the sentence, and what would have been the subject of the normal (active voice) sentence becomes the agent, and may or may not be indicated.

What they are

For the sake of clarity, let's give some English examples:

• The boy ate the hot dog. (normal sentence in the active voice; note that "the hot dog" is the object of the verb "ate")
• The hot dog was eaten by the boy. (the same sentence in the passive voice; "the hot dog" is now the subject, and "the boy" is the agent)
• The hot dog was eaten. (also in the passive voice, but with the agent omitted)

Now let's see those same sentences in Chinese:

• 男孩 吃 了 热狗。
• 热狗 被 男孩 吃 了。
• 热狗 被 吃 了。