You can use these in the present perfect (or past perfect) tenses: "ever" usually used in questions to ask "at any time in your life", example: Have you ever been to London? (Have you "at any time in your life" been to London?) "never" often used in answers (not usually questions) to say "not at any time in my life", example: I have never been to New York (I have "not at any time in my life" been to New York). "yet" can be used in questions or answers always at the end of the sentence, and implies that you haven't done something but you probably will in the future, example: I haven't been to Russia yet (I have "not at any time in my life" been to Russia [but I want to go and will go next year]). Why don't you try making some examples in the notebook on here?