[ابو بيشو]

Sally had agreed to wait in the pumpkin ***** with Linus before she realized that there was no such thing

as the Great Pumpkin. Both events happened in the past—agreeing to wait in the pumpkin ***** and

realizing that there was no Great Pumpkin—but the agreeing happened even before the realizing, so we

have to use the past perfect tense for the agreeing part and the regular past tense for the realizing part.

We might be tempted to say Sally agreed to wait in the pumpkin ***** with Linus before she realized that

there was no such thing as the Great Pumpkin, but we’d be wrong. Just using the regular past tense for

both parts of the sentence doesn't work because one event happened before the other event.
By the time Elysee discovered her sister, people had forgotten about the twin study.
I had always thought that I was an only child, but I recently discovered that I have a sister.

It wasn't until I saw her face that I realized how big the problem was.

So, my question is whether it is ok to use both past simple and past perfect with "It wasn't until ..."

An example:

It wasn't until I saw/had seen her face that I realized how big the problem was.

If there is a difference in meaning, it's very subtle. I suppose you could make an argument for logical sequencing that would give preference to 'had seen'; after all, it occurred before 'I realized'. Nevertheless, I'd feel very comfortable to use either. The same thing would probably hold true for 'after': 'After I saw her face, I realized how big the problem was'./ 'After I had seen her face, I realized how big the problem was.'
فعلا من المعروف انه اذا وجدنا realise/discover/remember/forget/find
ياتى بعدهما ماضى تام ولكن ماذا يعنى قولنا :had been wrong
وايهما الافضل :had been wrong /was wrong
الفعل هنا يعبر عن كون الشىء خطا وليس فعل action سبق الفعل الاخر فى حدوثة