Hi From Germany

[Unregistered]

cOULD YOU PLEASE EXPLAIN THE TWO FOLLOWING TENSES

I have never met anyone famous
and
i go shopping at least twice a week

Thanks

[Mohammed Abu Risha]

I have never met anyone famous before.

Here, you have used the present perfect. By using this tense, you mean in the sentence that you have never seen a famous person in your whole lifetime (i.e. up till now).
and
i go shopping at least twice a week

Here, you have used the present simple to express a habit: (It is my habit that I go shopping twice a week.)