Which sentence -- exactly as written -- is correct below? And why? When would we use one over the other? Are they both correct but carry different meanings? They seem as though they mean the same thing, but I think I'm wrong. He slipped and fell in aisle seven yesterday. OR He had slipped and fallen in aisle seven yesterday. Thank you.
They're both grammatically correct, to my eye. I'm not a grammarian, but I'm pretty sure the first one is simple past tense, and the second one is past perfect. The 'perfect' indicates that the action is complete. So, it would depend on your context which one you wanted to use. In this context, I can't really think of an example that would clarify the context issues, because "slipped" and "fell" are both pretty hard to do for very long at a time, and with "yesterday" added it's clear that the action is complete. I'd be likely to use the past perfect, but might change that if the rhythm of the paragraph felt off. Other examples make the distinction more clear. He visited the zoo every day. - makes it sound as if he'd done this in the past and might still be doing it, vs. He had visited the zoo every day. - implies that he's no longer doing that.
The first one is fine. To me, the second sentence is in the past, referring to an event further in the past. That makes "yesterday" rather ambiguous. So I would change the second one to: He had slipped and fallen in aisle seven the day before.
They're both correct. The first is simple past tense. The second is past perfect. It is used to talked about "the past in the past," or as mentioned above, something further in the past. For example, you would use the second sentence if you wrote something like: He had slipped and fallen before he went to the hospital.
If it is day t when you say "yesterday", then "yesterday" means day t-1. "Yesterday, he slipped and fell" means "He slipped and fell. Some time later, the day ended, then a new day began, which is the day on which these words are coming out of my mouth/pen/keyboard." Without the context, I cannot say which sentence communicates what you want to communicate. Past perfect ("he had slipped and fallen") is only necessary if simple past "he slipped and fell" misleads the reader into thinking the events happened in the wrong order. For example: "His back was broken. He slipped and fell in aisle seven." indicates that he was already in the condition of having a broken back, and then he slipped and fell. Here is how to correct that: "His back was broken -- he had slipped and fallen in aisle seven." (Putting the second thought in past perfect makes it clear that it comes before the first thought. That is the function of past perfect. Past perfect refers to a point in time before past.) If the story is narrated in past tense, then I would use past simple ("he slipped and fell") only if the sentence does not interrupt a series of events. For example: "He has always been a clumsy person. For example, he slipped and fell in aisle seven yesterday." Confusing? It is. Writing the story in the present tense would eliminate that confusion: "His back is broken -- he slipped and fell in aisle seven yesterday." One of many reasons why I recommend present tense.
