گزینههای پاسخ: DE,SE:Inapplicable ; RU:Inappropriate response; Missing{Inap, Not asked in survey, Not applicable, No answer, Don´t know, A great deal, Quite a lot, Not very much, None at all
گزینههای پاسخ: Never or almost never, Some lessons, Many lessons, Every lesson or almost every lesson, Valid Skip, Not Applicable, Invalid, No Response
گزینههای پاسخ: DE,SE:Inapplicable ; RU:Inappropriate response; SG: Refused;, Not asked in survey, Not applicable, No answer, Don´t know, A great deal, Quite a lot, Not very much, None at all
گزینههای پاسخ: Never or almost never, Some lessons, Many lessons, Every lesson or almost every lesson, Valid Skip, Not Applicable, Invalid, No Response
