Research questions
The specific research questions are listed as follows:
1. To what extent is the textbook effective according to the layout and design?
2. To what extent is the textbook effective according to the activities?
3. To what extent is the textbook effective according to the skills?
4. To what extent is the textbook effective according to the language type?
5. To what extent is the textbook effective according to the subject and content?
6. To what extent is the textbook effective according to whole Aspect?