It's likely you're thinking of a prepositional phrase, which is a common grammatical structure.
Here's what a prepositional phrase is:
* A group of words that starts with a preposition (e.g., "in," "on," "at," "to," "from," "with," "by," "about")
* Followed by a noun or pronoun (the object of the preposition)
* It acts as an adjective or adverb, modifying a noun or verb in the sentence.
Examples:
* The book on the table (prepositional phrase acting as an adjective modifying "book")
* I walked to the store (prepositional phrase acting as an adverb modifying "walked")
It's important to remember: A clause always contains a subject and a verb, while a prepositional phrase does not.
Let me know if you have any other questions about grammar!