What does it mean to be a double-qualified teacher in teacher recruitment?

Double-qualified teachers are the characteristics and key points of the construction of higher vocational teachers. It has become the unanimous voice of society and education to vigorously strengthen the construction of "double-qualified" teachers. Scholars have classified the understanding of "double-qualified" teachers into three types:

One is the "double certificate theory", which holds that those who have technical positions such as engineers and craftsmen, obtain teacher qualifications and engage in vocational education and teaching are "double-qualified" teachers;

The second is the "dual-ability theory", which holds that teachers who are competent in theoretical teaching and can guide students' practice can be regarded as "double-qualified" teachers;

The third is the theory of "double integration", which emphasizes both teachers' "double certificates" and teachers' "double abilities". However, no matter what kind of generalization, the understanding of "double-qualified" teachers in education circles is a literal explanation on the one hand and a more rational comprehensive explanation on the other.