Learn Hardcore Korean: hoeui jeone seoryureul hwaginhae juseyo. - Please check the documents before the meeting.

전에 is a postposition that marks “before” in time. When you attach 전에 to a noun—here 회의(“meeting”)—it creates a temporal adverbial phrase meaning “before the meeting.”

Why do we say 회의 전에 and not 회의를 전에?

회의 in this sentence isn't the direct object; it’s marking when something happens, so we don’t use the object particle 를. Instead, we form an adverbial phrase 회의 전에 (“before the meeting”) by adding the time marker 전에 directly to 회의.

Why is there no subject in 회의 전에 서류를 확인해 주세요?

Korean often omits the subject when it’s obvious from context. Here the implied subject is you (the person being asked). In English we’d say “You check the documents,” but in Korean the “you” is left out.

Why is 서류를 marked with 를 instead of 가?

를 marks the direct object of a verb, and 확인하다 is a transitive verb (“to check/verify”). So 서류를 shows that “documents” are what you need to check.

Why isn’t 서류 pluralized as 서류들?