복합관계사 + whether vs if

whoever = 주어 역할 Whoever submits first will get a bonus. → 빈칸 뒤에 동사(submits)가 바로

whomever = 목적어 역할 Forward the memo to whomever it may concern. → 빈칸 뒤에 S(it) + V(may concern)

① 명사절 주어 (if ✕) Whether the proposal is approved depends on the budget.

② 전치사 목적어 (if ✕) We're concerned about whether the shipment will arrive.

③ to부정사 앞 (if ✕) I haven't decided whether to accept the offer.

④ or not 직후 (if ✕) Whether or not to proceed is still under discussion.

⑤ 보어절 (if ✕) The question is whether we can afford it.

관계대명사 → 뒤에 불완전한 절 (주어/목적어 빠짐) The report [which the manager submitted ___] was approved. → 목적어 빠짐

접속사 that → 뒤에 완전한 절 The manager confirmed [that the report was approved]. → S + V 완전