Complex sentence: In the alternating method there is no problem of breathlessness or interruption as breath is taken when one whistles breathing in, but a disadvantage is that many times, the consistency of tone is not maintained, and it fluctuates.
Split into simpler sentences: In the alternating method there is no problem of breathlessness or interruption as breath is taken when one whistles breathing in. But a disadvantage of this method is that many times, the consistency of tone is not maintained, and it fluctuates.