Complex sentence: San Mateo High School is an American National Blue Ribbon comprehensive four-year public high school in San Mateo, California serving grades 9--12 as part of the San Mateo Union High School District.
Split into simpler sentences: San Mateo High School is a National Blue Ribbon comprehensive four-year public high school in San Mateo, California, United States. It serves grades 9--12 and is part of the San Mateo Union High School District.