So what would be the question you are asking? if you're asking how to hook a reader in your intro start with an onomatopoeia or something like: On a dark and stormy night Elle Mist sat in the corner of her room crying wondering when her parents would come home.
Foreshadowing means to give hints of the future. Like in "A Tale of two cities" by Charles Dickens, a man writes "Blood" on the wall, that word represents that there's probably a war coming.
Use of subordinate clauses is more of a grammatical thing, and if the writer is not sure if a sentence is correct he/she may ask a peer reviewer to edit or comment on it. However, the body of the essay is a standard for every essay assigned and it should be much easier for the writer to tell if he/she is following the rules.
c) As the sun set, the nocturnal animals began stirring.
