What is an example of an interjection?

An interjection is a word or phrase that expresses strong emotion or surprise, often standing alone in a sentence. "Oh dear!" exemplifies this definition perfectly, as it conveys a feeling of concern or dismay. Interjections often punctuate conversations or narratives, allowing speakers or writers to communicate feelings in a quick and impactful way.

In contrast, the other choices—such as "But," which is a conjunction; "Swiftly," which is an adverb indicating manner; and "Before," which functions as a preposition or conjunction—do not serve the same purpose of expressing an emotional response or exclamation. Hence, "Oh dear!" stands out clearly as the correct example of an interjection.