Macbeth Recitation: I want to do the witches' spell double double toil and trouble?

But the witches' dialogue only contains the description of the contents they're adding into the cauldron, like bones, eye of newt lizard's leg and stuff like that. They would make a great drama presentation, but I have to write a 200 word explanation to my recitation lines also. Do you think they have any importance to the plot, theme, motifs and imageries in the play Macbeth? Do you think I should have chosen a better scene and lines instead?