Past experience with 过 — Chinese grammar (HSK 2)

Subject + Verb + 过 + Object

过 (guo) after a verb means you have had the experience of doing something at some point, like English "have ever ...". The focus is on the experience, not on a specific occasion. The negative uses 没有 before the verb and keeps 过: 没有去过.

Examples

我去过北京。 Wǒ qù guo Běijīng.	I have been to Beijing.
他没有吃过羊肉。 Tā méiyǒu chī guo yángròu.	He has never eaten lamb.
你看过这个电影吗？ Nǐ kàn guo zhè ge diànyǐng ma?	Have you seen this movie?

Tip: 了 says an action was completed; 过 says you have the experience, so 我去了北京 and 我去过北京 are different.