E-tutorial systems recently played important roles in the teaching and learning of both online and conventional courses. Students have opportunities to study and practice exercises under guidance of the systems. A challenge in the development of e-tutorial systems is the design and implementation of the student guidance system. The guidance system should take into consideration the ability of individual students and give appropriate questions according to the student's ability. The students should finally reach the solution and gain better understanding of the learning topic. This paper presents the student guidance system of ESBO, a knowledge-based Physics e-tutorial system. This system considers individual student's ability in a different approach from other existing systems.
