Fill in the Blanks (Reading & Writing)

For centuries, fire had to be —carriedcarryingcarriagecarrier from embers or struck with flint, a slow and unreliable process. The invention of the friction match in the early nineteenth century meant a flame could be —producedproducingproductionproduce within seconds by anyone carrying a small wooden stick. Early formulations, however, relied on white phosphorus, a substance later —discovereddiscoverdiscoveringdiscovery to be a serious health hazard for factory workers. Safer red-phosphorus matches eventually —replaceddisplacedsubstitutedexchanged the dangerous originals.