sentence2_structure: a substance<>has<>a ph value greater than 7
sentence1: The user specifies the substance (e.g., citric acid or ethylenediamine), the desired pH, ionic strength, and volume, and the program indicates quantity of the substance to be used along with the calculated amount of strong acid or strong base required to achieve the desired pH.
sentence2: If a substance has a ph value greater than 7,that indicates that it is base.
question: If a substance has a ph value greater than 7, what does it indicate?