Since katherine proofread the recommendation report, you should finish the slide deck for the presentation. compound-complex complex simple

"Since Katherine proofread the recommendation report, you should finish the slide deck for the presentation" is a complex sentence.

Explanation: A complex sentence is a sentence made up of an independent clause and a dependent clause. While an independent clause can stand alone as a sentence, a dependent clause cannot as it does not present a complete idea. Moreover, unlike an independent clause, a dependent clause is introduced by a subordinating conjunction. In the sentence provided, "Since Katherine proofread the recommendation report" is a depending clause because it cannot stand alone as a sentence and it has been introduced by the subordinating conjunction "since". On the other hand, "you should finish the slide deck for the presentation" expresses a full idea; therefore, it is an independent clause. In that way, as the sentence provided is made up of a dependent clause and an independent clause, it is a complex sentence.

first, zeus made it thunder, then, athena sent her shield :)

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