Answer:
Your answer would be that the complete sentence is "the parade was cancelled".
Explanation:
For a group of words to be considered a complete sentence, it should contain a subject, a verb, and it must represent a complete thought. These are the elements that made up an independent clause which means that said group of words can stand alone as a sentence because it represents a complete idea. It does not depend on any other element to complete its meaning.
1) Before reading the book, Amanda drank a cup of coffee.
2) *Before reading the book
3) Amanda drank a cup of coffee
As you can see, 1 is a complete sentence made up of a independent clause and a dependent one (a complex sentence). When you separate the clases, you can see that one construction can stand alone as a sentence (3), and the other one fails to do so (2). This is the case because one clause depends on the other to complete its meaning, it neither contains a subject nor a verb (2). On the contrary, (3) contains a subject (Amanda), a verb (drank) which takes an NP D.O (a cup of coffee), creating a complete idea which functions as a sentence.
