whether inquiry teaching can improve students' critical thinking ability and cultivate students' scientific process skills is the most difficult problem that some scholars are committed to studying. Therefore, although the Journal of Science Teaching and Research has published several articles on the influence of inquiry environment on various cognitive abilities, the most studied one is classification ability. In 1966, J. Scott studied the ability of young children to classify familiar pictures. The research was conducted after children spent a period of time engaged in the exploration of Sachman model. Scott has done two more studies since then to examine the long-term impact of teaching methods, so his research is worthy of attention. In his research, middle school students received inquiry teaching for three years, and then these students were tested five years later. The results showed that students who accepted Sachman inquiry mode had better classification ability than their peers. In 1973, E.Boyd and others experimented with deaf children. The content of the experiment was to train students' hierarchical classification skills. The results showed that children who accepted inquiry teaching learned classification better than those who did not. In 1983, L. Radland made a study on Mexican-American students learning English in bilingual environment. The students in the experimental group took part in 3 45-minute inquiry activity classes for 12 weeks. The results showed that the experimental group had better classification ability and better oral expression skills than the control group. Based on this, the researcher draws the conclusion that inquiry should be an integral part of bilingual education.

The second aspect of process skills examined by researchers is general process skills, which mainly refers to observation, measurement, the use of numbers, guessing and so on. Schemansky (J.A.Shymansky) compared the differences in general process skills of fifth-grade students under the conditions of independence and teacher guidance. The experimenter examined the behaviors of both teachers and students. Students' designing classroom teaching structure by themselves is considered as inquiry teaching. Students who participate in this kind of teaching scored higher overall than those who participated in the teacher's designing classroom teaching structure, especially those with low level performed better in the classroom teaching with their own designing structure.

The third aspect of research is critical thinking ability. In 1967, J.S.Zingro and others conducted a comparative experiment on six groups of students, among which three groups of students participated in the traditional classroom teaching of proving experiments and the other three groups participated in structured inquiry. The results show that inquiry teaching can improve students' critical thinking ability in physics more than traditional teaching, but there is little difference in general critical thinking ability. Another example is A.M. RNGE's research in 1972, which required students to complete an experimental unit centered on collecting data about weather. When designing the unit, the "teacher variables" were kept to a minimum, and students were required to complete it themselves. Different from other studies, this study found that the students in the experimental group had greatly improved their critical thinking ability than those in the control group. Only these improvements are mostly limited to the parts emphasized in the experimental unit.

There are also some studies that show that inquiry teaching has no obvious promoting effect on developing students' process skills and critical thinking ability. In 1977, Stalin made a comparative experiment of inquiry teaching with grade 7 students. Although there was little difference in the ability level between the two classes of teachers, the results of the researchers' examination of process skills and critical thinking ability showed that there was no significant difference between the experimental group and the control group in these two aspects. In addition, the comparison between E.Charen's demonstrative experiment teaching and open experiment teaching shows that neither teaching is dominant in cultivating students' critical thinking ability.