I had finished it by 11 am

Question

I was told to that it was incorrect to say:

I had finished it by 11 am

The person was saying Past Perfect could be used only with Past Simple, not times like this one. What do you think about it?

Answer 1

The person is wrong.

The past perfect is used when the speaker wishes to relate the event to some more recent time in the past. That more recent time might be the time of some other event, but it might be some moment when nothing in particular happened, but the speaker wishes to set the temporal focus or viewpoint to then.

If you say "I had finished it by 11 am" you are mentioning it with respect to a later time, which is your temporal focus: that later time might be when you did something, or a time you are remembering, or maybe a time that somebody asked you about. If you are writing a story, you could even set the temporal focus by beginning with a past perfect "I had finished my story by 11 am", and the reader knows that you are viewing it from some later time, and expecting you to continue with what happened at that later time.

Answer 2

I handed in the paper at 12, because I had finished it by 11 a.m. Sounds good to me. The past perfect is used to show that something happened before something else in the past. Maybe that is what the person meant, that the past perfect is used in relation to another event? Or maybe you misunderstood?