story: My mom had a 75 gallon fish tank. She had friendly freshwater fish in there. Every one of her birthdays, I bought her shark for her tank. I tried to turn her sweet tank into a shark tank. To my shagrin, all the shark died and were eaten by the sweet fish.
 selected sentence: My mom had a 75 gallon fish tank.
My mom has a fish tank >Causes/Enables> I buy my mom sharks