An irregular word problem test was administered to 123 students from the second to fourth grades by experimental methods and clinical interview methods in order to explore the representation strategy difference between excellent and poor students when solving these problems.

A word problem test was administered to 123 students from the second to fourth grade by experiment method and clinical interview method, in order to explore the difference of representation strategy between superior students and inferior students when they solved comparable word problem.

This research employed the eye-movement approach to analyze the eye-moving features of the subjects when they were solving mathematical problems and discussed the reasons behind the representation strategy from the perspective of meta-cognition.

Results of problem solving,it showed that: problem representation strategy in solving compare problems is significance in different grades.

The present study will explore the development of self-presentational strategies and motives in 8-,10-,12-years-old elementary school students, in order to enrich and deepen the researches about self-presentation in developmental fields.

The main rule is that the system independently detects faults and takes countermeasures according to the pre - set strategy table,such as load shedding,generator trip or valve fast shut.

This paper introduces briefly the operation, function and the structure of strategy table of stability control equipment in Ertan hydropower plant.