Prepositional phrases are groups of words that begin with a preposition and end with its object. The object is usually a noun, pronoun, or noun phrase, and it can include modifiers like articles and adjectives. The whole phrase adds information such as location, time, direction, cause, or method. A basic pattern is preposition + object, sometimes with extra words in between.

Every prepositional phrase has a preposition and an object of the preposition. The object answers what or whom after the preposition, and it can be a single word or a longer noun phrase. Modifiers can appear between the preposition and the object, but the object is still the head noun or pronoun at the end of the phrase. Some phrases also include coordinated objects, where one preposition applies to two objects.

Prepositional phrases function as modifiers in sentences. They can modify nouns to add detail and identify which person, place, or thing is meant. They can also modify verbs, adjectives, or adverbs to explain circumstances like where, when, how, or why something happens. Understanding what the phrase modifies helps you place it correctly and avoid ambiguity.

When a prepositional phrase modifies a noun, it usually comes right after that noun to specify it. This use often answers which one, what kind, or whose, and it helps narrow meaning. Noun-modifying prepositional phrases frequently appear in descriptions and in more formal writing. If the phrase is far from the noun it modifies, the sentence can become confusing.

When a prepositional phrase modifies a verb, it adds information about the action, such as place, time, manner, purpose, or cause. These phrases often answer questions like where, when, how, or for what reason. Verb-modifying prepositional phrases are flexible in position, but moving them can change emphasis or clarity. Some verbs commonly combine with certain prepositions, creating natural-sounding patterns.

Prepositions often signal common relationships, and the phrase as a whole expresses that relationship. Many phrases describe location or movement, like place and direction, while others describe time, duration, or frequency. Prepositional phrases can also express cause, purpose, possession, comparison, and accompaniment. Context matters because one preposition can express different meanings in different situations.

Word/Phrase	🇨🇳 中文 单词/短语	Definition	🇨🇳 中文 定义	Example	🇨🇳 中文 示例
in	📌 在	inside a place or within a time period	📌 位于一个地点内或在一个时间段内	in the room	📌 在房间内
on	📌 在	on a surface or on a day/date	📌 在表面上或在日期/日子上	on the table	📌 在桌子上
at	📌 在	at a specific point in space or time	📌 在空间或时间的特定点上	at 6 p.m.	📌 下午6点
to	📌 到	direction or destination	📌 方向或目的地	to the station	📌 到车站
from	📌 从	starting point or source	📌 起点或来源	from the office	📌 从办公室
with	📌 与	accompaniment or using an instrument	📌 伴随或使用乐器	with a friend	📌 与朋友一起
for	📌 为了	purpose, benefit, or duration	📌 目的、收益或持续时间	for two weeks	📌 为期两周

Prepositional phrases often appear after the word they modify, especially when they modify nouns. When they modify verbs, they may appear at the end of the clause, at the beginning for emphasis, or near the verb for clarity. Good placement reduces confusion when multiple phrases appear in the same sentence. If a phrase could logically attach to more than one word, move it closer to the intended target.

English often uses multiple prepositional phrases in a row to add layers of detail. Stacking is common in descriptive writing, but too many phrases can make sentences heavy and hard to follow. To improve clarity, keep each phrase close to what it modifies and consider breaking long stacks into separate clauses. When two phrases describe different targets, separate them clearly through ordering or restructuring.

The object of a preposition is usually a noun phrase, but it can also be a pronoun or a noun-like word group. After a preposition, English uses object pronouns, not subject pronouns. The object can include determiners, adjectives, numbers, and other modifiers. In some cases, the object can be a gerund, which behaves like a noun in the phrase.

Rule	🇨🇳 中文 规则	Example	🇨🇳 中文 示例
Use object pronouns after prepositions	📌 介词后使用宾格代词	with me	📌 和我一起
The object can be a full noun phrase with modifiers	📌 宾语可以是带修饰词的完整名词短语	in the small blue box	📌 在小蓝盒子里
A gerund can be the object of a preposition	📌 动名词可以是介词的宾语	by studying	📌 通过学习
One preposition can apply to two coordinated objects	📌 一个介词可以作用于两个并列的宾语	between you and me	📌 在你和我之间

Some short words like in, on, up, and out can be prepositions or particles. A preposition must have an object, forming a prepositional phrase. A particle is part of a phrasal verb and may not take an object, or the object may belong to the verb rather than the preposition. Identifying whether there is a true object of the preposition helps you decide which role the word is playing.