俺がボクシングしてるとこ見たことある？って英語でなんて言うの？

"Before" in this case means "have you ever." You can use this both in American and British English. I hope that this helps! :)

There is really only one way to ask this question, and this is to directly come out and ask it: "Have you ever seen me boxing?"

By using this question, you should get a yes or no answer in response. 'Have you ever seen me boxing?' 'No, not yet'

Boxing is a sport which involves two players trying to hit or knock each other down with gloves on usually in a boxing ring If you want to ask someone if they have seen you do something then you coulld ask 'have you ever seen?' or 'have you seen me?' before suggests it is the first time of seeing/doing something

Did you ever come to one of my boxing fights/practices? This implies that you used to box or that you are currently taking a break from boxing and you are now talking about something that you used to do continously. You haven't seen me box have you? This is more a common way that you can ask about whether or not someone has seen you box. it can be used as a conversation starter.

If you want to ask if someone has seen you box before you can ask the question like this: "Have you seen me boxing yet?"

when asking someone if they have ever seen you boxing before, you can say something simple like "Have you seen me me box before?." or "I was wondering if you have ever watched me boxing before". The second example is an even more polite way to ask someone if they have ever seen you box before.

The most formal way of asking someone if they had seen you box before would be to say "Have you ever seen me boxing before?" To which they would reply with "Yes I have" or "No I haven't".

You want to ask a friend if they have ever seen you boxing. For this construction, we need to use the present perfect form (for life experience). The time frame stretches from this moment to the day you were born. Of course, if the scenario has no connection with the present ie you are not in a boxing gym, or in the process of training or fighting, then you may choose to use the past simple form as in the second example. Eg "I've never travelled by plane (before)." 'Before' is not necessary in this sentence but it seems to be common usage in the UK.

To ask if someone has done/seen something in the past, you say "have you seen/done... before?" In this case, you would use the verb in the infinitive (i.e. "box") Likewise, you can also ask the same thing, but say instead "have you ever seen/done ...?" In this case, you would use "me" + the verb in the -ing form. (i.e. "have you ever seen me dancing?") Therefore, it would be appropriate to say either "Have you seen me box before" or "have you ever seen me boxing?" Each way would be commonly understood and are natural ways of asking.