There are many types of questions that a tutor can use in a tutoring session. Good questioning techniques are essential to a successful tutoring session. It is important to use the right words. If you ask students what they don't understand, they will be clueless. Another important aspect of asking questions is waiting for an answer.
Many tutors are too qui to answer their own questions.
Give students an opportunity to reflect on the question before they volunteer a response. Always wait at least 20 seconds for the student to answer your question. Remember to ask leading questions. Become familiar with the Socratic Method of teaching. It is the oldest, but still the most powerful teaching tactic for fostering critical thinking.