sentence2_structure: a substance<>has<>a ph value greater than 7
sentence1: Based on the list provided of the uses of substances 1-7, estimate the pH of each unknown and record the number in the data table in the estimated pH column.
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?