1. A crash course in refrigeration maintenance of Huacheng Vocational School in Heze City, Shandong Province, and AAA Huacheng Vocational School in Heze City, Shandong Province, provide a broad platform for employment and entrepreneurship development for migrant workers, laid-off workers and unemployed people.

2. Refrigerator, refrigerator classification, refrigerator structure, refrigerator refrigeration system, common refrigerator circuit, household electric freezer, new refrigerator technology, refrigerator fault detection and maintenance, common refrigerator fault phenomena and detection methods, refrigerator box fault analysis and maintenance, refrigerator refrigeration system fault analysis and maintenance, refrigerator control circuit system fault analysis and maintenance, and refrigerator common fault analysis and treatment.