used to mean "visited" or "travelled",

I've never been to Kenya, but I hope to visit it next year. 我从未去过肯尼亚，我希望明年去看看。

"Have you ever been there before?" - "Yes, I've been twice." "你以前去过那里吗？" - "是的，我去过两次。"

used as the past participle of "go" when the action referred to is finished

She's been to the hairdresser's (= and now she has returned). 她去过理发店了。

Do you need to go to the bathroom, or have you already been? 你需要去洗手间吗？还是说你刚去过了？

used to mean "arrived"

The postman hasn't been yet. 邮递员还没来。

The doctor's just been (= has arrived and left). 医生刚才来过。