Answer:
The italicized noun clause "That he run the mile in less than four minutes" Functions as an Appositive.
Explanation:
Appositive is usually a noun phrase that renames another noun or phrase. The italicized noun clause "That he run the mile in less than four minutes" is a good example of Appositive.
Appositive can be a combination of short or long words, they generally can be referred to as two nouns by which one identifies or defines the other, therefore they work well together. Adding an Appositive to a sentence does not mean that a sentence is incomplete but instead it adds more information about the other noun presented.
a roes bush, a tooth pick, a knife, my elbow.
