here is field name of table.
    student_score: name, chinese, math, english, total_score
    student_gender:  name, gender, class
    
    user commands: 
    Please provide an SQL command and perform the following actions: Merge database tables' student_score 'and' student_gender ' by ' name ' and find everyone with a class of 1,2 and chinese > 70 and calculate the average value of 'math' and 'english' 