When the deputy president comes to Parliament he must speak about things he understands, EFF MP Mbuyiseni Ndlozi told David Mabuza on Tuesday after he dodged a question asking him to define the first, second, and third industrial revolutions.In February, Mabuza's rambling answer after he was asked to define the fourth industrial revolution left opposition MPs dumbfounded.During Tuesday's question session in the National Assembly, a question about the fourth industrial revolution again adorned the question paper. Ndlozi asked Mabuza what the first three industrial revolutions were, with the ANC shouting him down.He also asked Mabuza how nanotechnology would affect medical procedures."In terms of the first, second and third, probably that is a new question," Mabuza said."Now you're taking me back to the feudal way of doing things."I'm prepared to explain if you ask a new question," Mabuza said.WATCH: @belbozz asks Deputy President David Mabuza to define the 4th industrial revolution.His answer will shock you! #MabuzaQandA pic.twitter.com/iNYXrTiWZm— Democratic Alliance (@Our_DA) February 27, 2019He spoke some more about the fourth industrial revolution, while opposition MPs shook their heads. Ndlozi sat frowning, with arms folded across his chest.When Mabuza concluded, without dealing with nanotechnology at all, DA chief whip John Steenhuisen rose on a point of order. "I think the deputy president needs to phone a friend," he said, evoking the quiz show Who Wants To Be a Millionaire.Speaker Thandi Modise said that was not a point of order.Ndlozi then rose and said: "I really want to impress upon you, deputy president, don't come to Parliament to speak about things you don't understand."Modise said that was not a point of order but a point of information.Turning to Modise, Mabuza said: "I said the question on the first, second and third is a new question. Is that wrong?"Opposition MPs were clearly not in the mood to let him of the hook."Let's not do this. Honourable Ndlozi made his point. He said please brush up on the other revolutions. Please, let's leave it at that," said Modise.