Complex sentence: When a person masters T'ai chi, their body becomes impregnable to any weapon, but has a side effect of turning the person's hair white by age thirty and their voices attain a high tone.
Split into simpler sentences: When a person masters T'ai chi, their body becomes impregnable to any weapon. But a side effect of mastering T'ai chi is that the person's hair turns white by age thirty, and their voices attain a high tone.