Singular & Plural :)
We have already talked about singular and plural forms. We have to always keep in mind that when we form a sentence everything has to match in number, case, and gender!
There are some cases when we address only 1 person and still we use plural! It similar to saying: "We want ice-cream" when it's just you in the room!
Why is this happening? Because in Greek, we use the polite/ form that is used daily...
When we address someone we don't know, our boss, an elderly person, or simply someone we want to address with respect, we use plural. That means, you will say " Τι κάνετε;" (plural) and not "Τι κάνεις" (singular).
Similarly, you will say, " Τι θέλετε;", "Πως είστε;" etc and not " Τι θέλεις;", "Πως είσαι" etc.
Some people will ask you to use the singular/ familiar form and then you can switch!
Or, you can take initiative and ask yourself- especially when talking to people of same age!