Before revision: For example, tap water is a substitute for Coke, but Pepsi is a product that uses the same technology ( albeit different ingredients) to compete head-to-head with Coke, so it is not a substitute.
After revision: For example, tap water is a substitute for Coke, but Pepsi is a product that uses the same technology ( alittle bit different ingredients) to compete head-to-head with Coke, so it is not a substitute.