Complex sentence: In "A Study in Scarlet" Holmes claims to be unaware that the earth revolves around the sun, since such information is irrelevant to his work; after hearing that fact from Watson, he says he will immediately try to forget it.
Split into simpler sentences: In "A Study in Scarlet", Holmes claims he does not know that the Earth revolves around the Sun, as such information is irrelevant to his work. Directly after having heard that fact from Watson, he says he will immediately try to forget it.