Complex sentence: An autotransformer does not provide electrical isolation between its windings as an ordinary transfomer does; if the neutral side of the input is not at ground voltage, the neutral side of the output will not be either.
Split into simpler sentences: An autotransformer does not provide electrical isolation between its windings as an ordinary transfomer does. Furthermore, if the neutral side of the input is not at ground voltage, the neutral side of the output will not be either.