-If you have any questions, I will be pleased to answer them at the end of the presentation.
-there will be time at the end of the presentation to answer your questions-so please feel free to ask me anything then.
-Don"t hesitate to interrupt if you have a question.
-Please feel free to interrupt me at any time.
-Please stop me if you have any questions.
-If you need clarification on any point, you"re welcome to ask questions at any time.
-Can I come back to that point later?
-I will be coming to that point in a minute.
-That"s a tricky question.
-We will go into details later. But just to give you an idea of...
-I am afraid there"s no easy answer to that one...
-Yes, that"s a very good point.
-Perhaps we could leave that point until the questions at the end of the presentation
-I think I said that I would answer questions at the end of the presentation---perhaps you wouldn"t mind waiting until then.
-I think we have time for just one more question