Πού = Where Πού είσαι; = Where are you? Το σπίτι που ζώ. = The house where I live. Πώς = How Πώς είσαι; = How are you?

You must first understand that verb+ing or to+verb are not a Main Verbs, they usually depend on other words in a sentence

It means..... " something ..in general", or "Not a particular". I think that a law which starts with "A....something" will face many interpretation problems.

The language that you will keep studying or practising without getting bored

Making a sentence is not just putting words together. I know. Always try to make small but correct sentences , even if they seem very simple. Make every correct simple sentence meaningful. I don't mean just to "know" the meaning of it, but to try to make it "your own". A sentence is not just a combination of words. It is something that we create to express ourselves.....as long as you want to express yourself in a way that makes other people understand you....then you are on the right path.

With Present Perfect always seek a connection to a present situation. In this case, the action took place in the past "last night", but the conclusion "you've been to" is related to a present situation. You can probably find counter examples for most grammatical rules, this does not mean that the rule is wrong. Keep in mind that grammar rules are about the most common language uses. Nine out of ten times, you cannot go wrong using proper grammar.....

Are you taking a risk now? Are you worried about how ppl might react to what you say?