Complex sentence: The input impedance of the circuit is almost zero because of the Miller effect; all the stray capacitances (the cable capacitance, the amplifier input capacitance, etc) are virtually grounded and they have no influence on the output signal.
Split into simpler sentences: The input impedance of the circuit is almost zero because of the Miller effect. Hence all the stray capacitances (the cable capacitance, the amplifier input capacitance, etc) are virtually grounded and they have no influence on the output signal.