premise: electricity is a kind of alternative fuel sent2: using a gasoline engine requires burning gasoline sent3: pollution has a negative impact on the environment / air quality / water quality / society sent4: an electric motor is a kind of electrical device sent5: as the use of alternative fuels increases , the use of gasoline will decrease sent6: if a certain something decreases the use of a resource then that certain something uses less of that resource than a regular something sent7: if a machine contains a part then that machine uses that part sent8: an electric car is a kind of machine sent9: using less of something negative has a positive impact.
hypothesis: an electric car has a positive impact on the environment / air quality / water quality / society by using less gasoline