Basketball has a precondition of create memorandum. Buy present has a precondition of spend money. Go to store has a sub-event of you will buy something. Drive car has a precondition of put it into gear. Spend money does not have a precondition of patent it. Spend money has a precondition of go to store. Buy present does not have a precondition of patent it. Buy food has a precondition of go to store. Buy present does not have a precondition of pump iron. Pass course has a precondition of create memorandum. Basketball has a precondition of put it into gear. Go to store has a precondition of drive car.
Buy present has a precondition of drive car.