Perhaps the most famous interjection in comics and Cartoons today is Charlie Brown's "Good Grief!"
No, "WOW" is not a preposition. "WOW" is an interjection expressing surprise or admiration in written form.
Interjection! Wow, that was a surprising turn of events.
Wow, that was an amazing performance! Ouch, that hurt! Hooray, we won the game! Oops, I dropped my phone.
The "Oh" is the interjection.
An interjection is a word that show surprise. As in: AH! A tiger! EEK! A mouse WONDERFUL, my darling. YES! I won!
An interjection is a word or phrase used to express emotion, often appearing in a sentence on its own or followed by punctuation. An exclamatory sentence is a type of sentence that conveys strong emotion, typically ending with an exclamation mark. While interjections can be part of an exclamatory sentence, not all interjections are exclamatory sentences.
An interjection or modifier perhaps.
"Wow, that movie was really exciting!"- Here, "Wow" is an interjection expressing strong emotion or surprise.
Wow
Yes, it is proper English to start a sentence with the word "oh." This interjection can be used at the beginning of a sentence to express a range of emotions or to call attention to something specific.
Hey
Wow! That was the fastest game I have ever seen!Wow, I had no idea that was possible!