Time Expression + 过去 + 了
The verb 过去 (guòqù) means "to pass by" or "to go past," often used to describe the passage of time. When used after a time expression, it indicates that a period of time has elapsed. For example, 几天过去了 means "a few days have passed."
一个星期很快就过去了。
Yī ge xīngqī hěn kuài jiù guòqù le.
A week passed by very quickly.
那段艰难的日子终于过去了。
Nà duàn jiānnán de rìzi zhōngyú guòqù le.
Those difficult days have finally passed.
青春一旦过去就再也回不来了。
Qīngchūn yīdàn guòqù jiù zài yě huí bù lái le.
Once youth is gone, it never comes back.