Hi Aispark
Never be afraid to ask your teacher to clarify something you don't understand. Asking questions is an important part of learning. Of course, don't ask the question in an aggressive or challenging way. A simple "would you please go through that again?, i don't quite understand...." or similar. Don't try "i went to teacher X and he told me something different". Even if this is true! Good teachers actually enjoy questions because it gives them the opportunity to assess the pupil's abilities or understanding, and thus provide better learning for them.