We present a design of a fully electrically tunable metasurface switch based on nematic liquid crystal (LC). By applying different voltages on adjacent gratings of the interdigitated electrodes, the dielectric constant of the LC material and the responses of the proposed metasurface can be arbitrarily tuned. The experimental results reveal a reflective switch action in the structure across a frequency range of 106.80 to 114.15 GHz. The maximum operational frequency bandwidth is 7%, and the highest switch contrast ratio achieved is 0.77. Moreover, the suggested structure demonstrates multifunctional switching capability, manifesting a transmissive switching effect in the frequency range of 340.75 to 345.13 GHz. The measured switch contrast ratio reaches a maximum of 0.71. Combining the advantages of multifunctionality and cross-spectrum application, we provide an innovative approach for developing switches intended for terahertz wave communication systems.