Answer:
Step 1: Putting parentheses around prepositional phrase
Step 2: Highlighting dependent clauses
Step 3: Making the subjects bold and underlining the simple predicates:
1) When the dog started barking (at the front door), Boris knew that his package had arrived.
2) A note that Olga wrote for her high school crush was hidden (in the spine of her favorite novel).
3) Since we ordered a pizza yesterday, I think that we should eat vegetables today.
4) The smoke alarm went off because Malik burned the toast that he was making (for breakfast).
5) It has been said that the ghost of the old woman always appears in the mirror (at the end of the hallway at the stroke of midnight).
Step-by-step explanation:
a) Prepositional phrase starts with a preposition, an object and another word that modifies the object.
b) A dependent clause is a statement that depends on an independent clause to make a complete sense.
c) A simple predicate is the word or group of words that show the action of the subject.
d) A parenthesis is a way of highlighting something to draw attention to it. In grammar, it is usually done with the use of brackets.