Introductory adverb

An introductory adverb is an adverb — or a longer adverbial word group — that opens a sentence before the main clause begins. It might be a single word (However, Meanwhile, Fortunately, Suddenly), a phrase (After the storm, In the morning), or a full adverbial (dependent) clause (Because the roads were icy). In each case, the introductory element frames when, where, why, or how the main clause happens, or signals a logical connection to the previous sentence.

The core punctuation rule is simple: an introductory adverb or adverbial is set off from the main clause with a comma. "However, the results were inconclusive." "After the game, we went out for pizza." The comma marks where the introduction ends and the sentence's main subject and verb begin. Writers sometimes omit the comma after a very short introductory phrase, but on standardized tests the comma is the expected answer.

Recognizing introductory adverbs also prevents a classic error: a conjunctive adverb like however or therefore cannot join two independent clauses with only commas. "The data was flawed, however, the team published anyway" is a comma splice; it needs a semicolon or a new sentence before however.

The ACT English section tests introductory adverbs directly — expect questions asking where the comma belongs after an introductory word or phrase, and questions that require distinguishing adverbs from other parts of speech.