Complex sentence: However, the gas the person buys during that year to fuel that truck would be considered a deductible expense because it does not improve or prolong the life of the truck but simply allows it to run.
Split into simpler sentences: However, the gas the person buys during that year to fuel that truck would be considered a deductible expense. The cost of purchasing gas does not improve or prolong the life of the truck but simply allows the truck to run.