This document discusses two grammatical concepts in Chinese: prepositional phrases and indefinite pronouns.
For prepositional phrases, it explains that they are formed with a preposition and noun, like "with a hat" or "in the kitchen." It gives examples of prepositions of place and time.
For indefinite pronouns, it notes that words like "someone", "anything", "everybody" are considered third person singular. It also explains that when modifying an indefinite pronoun, the adjective comes after rather than before.