You use a co-ordinating conjunction ("and," "but," "or," "nor," "for," "so," or "yet") to join individual words, phrases, and independent clauses. Note that you can also use the conjunctions "but" and "for" as prepositions.
Subordinating Conjunctions
A subordinating conjunction introduces a dependent clause and indicates the nature of the relationship among the independent clause(s) and the dependent clause(s).
The most common subordinating conjunctions are "after," "although," "as," "because," "before," "how," "if," "once," "since," "than," "that," "though," "till," "until," "when," "where," "whether," and "while."
Correlative Conjunctions
Correlative conjunctions always appear in pairs -- you use them to link equivalent sentence elements. The most common correlative conjunctions are "both...and," "either...or," "neither...nor,", "not only...but also," "so...as," and "whether...or." (Technically correlative conjunctions consist simply of a co-ordinating conjunction linked to an adjective or adverb.)
Interjection
An interjection is a word added to a sentence to convey emotion. It is not grammatically related to any other part of the sentence.
You usually follow an interjection with an exclamation mark. Interjections are uncommon in formal academic prose, except in direct quotations.
The highlighted words in the following sentences are interjections: Ouch, that hurt! Oh no, I forgot that the exam was today. Hey! Put that down! I heard one guy say to another guy, "He has a new car, eh?" I don't know about you but, good lord, I think taxes are too high!
Preposition
A preposition links nouns, pronouns and phrases to other words in a sentence. The word or phrase that the preposition introduces is called the object of the preposition. A preposition usually indicates the temporal, spatial or logical relationship of its object to the rest of the sentence as in the following examples: The