Answer:
The four words are:
"During the Chemistry experiment..."
Explanation:
The above words are the four words that make up the prepositional phrase.
A prepositional phrase is known to be a group of words which has a preposition with its object and other words that modify the object. Prepositional phrases can actually modify a noun or a verb.
Examples of common prepositions that actually begin prepositional phrases in sentences are: <em>to, about, during, behind, after, for, of, at, before, under, with, over, with, </em>and <em>by</em>.
The above sentences begin with a preposition and it is answering the question of when the smoke filled the class.
In Ancient times, sickness was thought to be caused by an excess of blood. Therefore, doctors would cut into their patients and let some of the blood out to help cure them. This theory advanced into thinking that the human body needed all of its "humors" to be balanced: blood was one of the humors so if the doctor thought you had an imbalance, they would 'let' some of the blood out.
