Business presentations and training sessions can be far more interactive then speeches, and presenters often don't face a traditional question-and-answer session. In many business presentations (especially informal ones during meetings), the best time for questions can be during the talk, as they come up. This is tricky for speakers, who risk losing their place and momentum. Try this approach only as you become a more experienced speaker. Allow yourself to be interrupted if you have to; if the boss asks a question that fits in, answer it, but as a rule, explain why you would like to hold questions until the end.
There are two general strategies for taking questions in training sessions: You can stop and answer as you go along, or you can take questions after each section of your presentation. The first strategy can get you sidetracked unless you control it carefully; however, the second one doesn't let people ask questions as freely as they can if you take queries as they arise. How to organize the Q&A period is always a dilemma for a speaker. The way you take questions must be decided by analyzing your purpose, the extent of your content, the size of the audience, and the amount of time you have been allotted.
Training meetings have a tangible goal: to transfer a skill or technique to the audience. If people don't have questions answered as you go along, you will lose them as their understanding and grasp of the new material slips. As a general rule, ask people to jot questions down as you go along, and stop every 20 minutes or so to take them. If you have someone who just isn't keeping up, don't allow the whole session to drag; you'll alienate the rest of your audience. I tell the person I realize the concept is difficult and that it took me a long time to master it. I then ask him or her to talk with me during the next break.