This is the 11786th most frequent Turkish word.
geliştirmişti
"Had developed."
In this sentence, 'geliştirmişti' is used to indicate that Ahmet had improved his project in the past as part of a completed action.
Ahmet bir yıl boyunca projesi üzerinde çalışarak geliştirmişti.
Ahmet had improved his project by working on it for a year.
Here, 'geliştirmişti' signifies that the scientist had formulated the theory sometime in the past prior to the current moment.
Bilim insanı yeni bir teori geliştirmişti, ancak bu henüz kanıtlanmamıştı.
The scientist had developed a new theory, but it was not proven yet.
In this case, 'geliştirmişti' describes that the company improved or enhanced the product before an event—its market release.