A preposition is a word used to express the relationship between people and people, or between things and things. It can indicate time, place, manner, object, reason, etc. A preposition is usually followed by an object, together forming a prepositional phrase. In a sentence, a prepositional phrase can function as an adverbial, and can also act as a complement or an attributive.

The typical structure of a prepositional phrase is 'preposition + object'; the object can be a noun, pronoun, verb phrase, or noun phrase. The relationship between the preposition and its object is tight, and other elements should not be inserted between them.

Common Chinese prepositions include '在','对','给','跟','从','向','往','为','把','被'. Each expresses a primary relation. Mastering these high-frequency prepositions covers most everyday expressive needs.

'在' is commonly used to indicate a specific time point or time span, introducing the time context. '从' is used to indicate the starting point of time, sometimes paired with '到' to indicate the range.

'在' is used to indicate the location where an action occurs and is the most common location preposition. '从' indicates the starting point, and '到' often corresponds with '从' to indicate the endpoint.

'对' is used to introduce the object of an action or emotion, common in 'be interested in ...' or 'be responsible for ...'. '给' can introduce the recipient, indicating handing something to someone.

'跟' commonly indicates being with someone, equivalent to companionship. '用' indicates the method or tool used to perform the action.

'向' and '往' both indicate direction; '向' emphasizes moving toward a target, '往' emphasizes the movement of the action. '到' indicates arrival at a destination.

'为' can express purpose or cause; its meaning depends on context. '因为' introduces a cause clause, but '为' is more commonly used as a preposition within phrases.

Prepositional phrases are most commonly used as adverbials, typically placed before the verb or at the sentence start. They can also function as complements or modifiers, but using them as adverbials is the most basic and frequent.

'Ba' is a special type of preposition used in 'ba' sentences to front the object, highlighting handling or result; 'bei' introduces the agent, forming a passive structure and emphasizing the affected entity. Both require specific syntactic structures and are not simply 'preposition + object'.