Writing sentences is an intricate part of English. Throughout school, students are taught the basics of forming good sentences. Knowing how to start sentences with prepositional phrases will help you better structure your text. Prepositional phrases are words in groups that have a noun or pronoun object and a modifier of the preposition. Examples of prepositions include words such as about, below, from, up and with respect to. By following a basic structure, you will make a proper prepositional phrase.

Step 1

Understand how to use prepositional phrases. Prepositions come before the object of the preposition. When you use words such as throughout or within before the object, then those words are prepositions.

Step 2

Identify prepositional phrases. Read a few sentences in a book. Identify the prepositional phrases. Locate the object of the preposition. Once you find the object, look before it and you will see the preposition. The ability to identify prepositional phrases in other sentences will prepare you to start sentences with them.

Step 3

Identify the right word for your sentence. To start your sentence with a prepositional phrase, you have to choose an appropriate word to begin with. An example is "Before the sun went down, she was asleep." The prepositional phrase is "Before the sun." "Before" is the preposition. "Sun" is the object of the preposition.

Step 4

Use a comma when the subject is not at the beginning of the sentence. Starting a sentence with a prepositional phrase allows for the use of commas. The introduction of the sentence is separated from the rest of the sentence. For example, "Despite her choice, she lost the game." Prepositional words that use commas after them include additionally, after all, also and instead.