When a teacher plans instruction, he has in mind some prototypical students or group: someone like himself or some group similar to his in ability. With this conception of the prototypical students or group, he teaches only one-third of students to reach a level of achievement. At the end of semester, most teachers give their grades, generally reflecting students' IQ scores, according to a normal distribution curve. There are good learners and poor learners, faster learners and slow learners in any classroom, mainly due to their inborn abilities or environment. We believe that all people are created equal, and deserve equal educational opportunity. Therefore, educational outcomes should be equal for all students in general basic education. Equality of learning outcomes and vertical equality in the learning process are very hard to achieve. Nevertheless, it has to be an ideal goal of schooling and a long-range objective of education reform. In accordance with the goal of schooling and education reform, the principal role of teachers should be teach all students to master their subject.