Everytime when you need to say “I wonder”, “I’m curious”, “I am interested” or “it is interesting” you can use a very good expression “мне интересно”.
Мне интересно
– it is interesting to me
Examples:
Мне интересно, как давно вы тут работаете – I wonder how long you work here.
Мне интересно, что ты тут делаешь? – I wonder what you’re doing here.
Also it is possible to say it without the pronoun “мне”
Интересно, откуда вы? – I wonder where you are from.
Интересно, как вас зовут? – I wonder what your name is.
The last expression for today with “интересно” is
Просто интересно
You can use it as an answer to a question “why are you asking?”.
It is like an English phrase “I’m just curious“.
– Сколько вам лет? (How old are you?)
– Почему вы меня спрашиваете? (Why are you asking me that?)
– Просто интересно (just curious).
It is very easy and short way to avoid the explanations the reason of your question.