Grammar question

<p>“In his memoir, Baker tells stories about the time before he attended high school, when he delivered newspapers to the huge estates and mansions that used to line the riverfront.”</p>

<p>This sentence has no error. But I have a verb tense question. “Had delivered” is a past participle used in place of a time before some past event. Since the delivering of newspapers happened before “he attended high school,” shouldn’t the sentence read: “…when he had delivered newspapers…”?</p>

<p>When there is an explicit signal word like “before” indicating the change in time reference, the past perfect is not always necessary.</p>