having done by / at
1. I remember my father having brought home a huge Christmas tree last year at 5 PM.
2. I remember my father having brought home a huge Christmas tree last year by 5 PM.
3. I regret not having done that yesterday at 7 PM.
4. I regret not having done that yesterday by7PM.
I have seen some people say in some internet sites that we must use a perfect infinitive (to having done) when actions are completed before a time limit, so; they say sentences 2 and 4 are correct. However, I would like to ask if sentences 1 and 3 are OK or not.
Re: having done by / at
Us of "at" in #'s 1 & 3 would indicate that the times stated were the precise/exact times at which the action(s) occurred (#1) or were to have occurred (#3).
Originally Posted by aysaa