question: What did an alternate version of the incandescent lamp substitute for a wire filament ?
answer: an arc struck on a spherical bead electrode
turker_answer: An alternate version of the incandescent lamp substitued an arc stsruck on a spherical bead electrode for a wire filament .
rule-based: An arc struck on a spherical bead electrode an alternate version of the incandescent lamp substitute for a wire filament .