Complex sentence: Until 1973, for an sound Genie had an optional rule allowing her to either delete it or substitute the sound The exception was that before 1973, with only one deviation, in a word-final position she would simply delete the.
Split into simpler sentences: Until 1973, for an sound Genie had an optional rule allowing her to either delete it or substitute the sound. The one exception was that prior to 1973, with only one deviation, in a word-final position she would simply delete the.