Jīngguò cháng shíjiān de xuéxí, wǒ zhōngyú tōngguò le kǎoshì.
After a long period of studying, I finally passed the exam.
Tips
usage
经过 as a verb means physically passing by a place. As a preposition before a noun, it means "through/after (a process)": 经过讨论 (after discussion), 经过考虑 (after consideration).