A comparative research on “Go For It” and “New Concept English” in both the surface structure and deep structure will be done in the study.

2.1.3 Functions of textbook

    Hutchinson, T. & Waters (1987) stated the functions of textbooks from the following six aspects:

(1) To motivate learner’s learning; 

(2) To be the correct and appropriate language model for language learning; 

(3) To widen the basis of teachers' training; 

(4) To help teachers organize the teaching and learning activities; 

(5) To embodies the compiler's natural language and learning view; 

(6) To provide a balanced view, which can not only reflect the complexity of the learning task, but also make it easy to manage.

    Teaching materials play an important role in language teaching and learning. They can not only concretely express the instructional objectives and teaching contents, but also influence the education environment, teaching procedure and teaching appraisal. In a word, textbooks are of vital importance to the physical and mental development of students.

2.2 Previous studies on textbook evaluation abroad and at home

2.2.1 The Related Studies abroad源`自,优尔`.论"文'网[www.youerw.com

2.2.1.1 Theoretical research on English textbook evaluation

    Tomlinson ( 1998 ) believed a elaborately designed textbook should be evaluated by the following characteristics: 

(1) The textbooks should have the appropriate form, content and theme, so that students can build up confidence without tension. 

(2) Textbooks should offer opportunities for learning feedback. 

(3) A variety of learning styles and emotional factors should be taken into consideration in teaching materials. 

(4) The textbooks should be capable to fulfill the requirement of learners, facilitate learning, provide language practice opportunities for students to achieve the goal of communication. 

(5) Teaching materials should allow students to develop their learning potential in the silent period, and encourage students to carry out intelligence, aesthetic and emotional intervention in order to stimulate the coordination ability of the left and right hemisphere.

2.2.1.2 Practical research on English textbook evaluation

  Vahid Nimehchisalem and Jayakaran Mukundan (2012) carried out a practical research on the evaluation of English textbooks in their thesis “Evaluative Criteria of an English Language Textbook Evaluation Checklist”. There are two research objectives in their study: 

(1) to what extent of significance of each section did the checklist has? 

(2) Which events should be assumed in the eventual checklist? 

     The checklist was shown to the respondents and the significance of each item from 1 (unimportant) to 5 (very important) was exacted to absorb and count in part two. The sample adopted by Vahid Nimehchisalem and Jayakaran Mukundan covered 210 English language teachers or instructor (60 male and 150 female, aged between 20 and 67).

    This study is conducted to exploit a checklist to evaluate the English teaching textbooks, the results are summarized at the end of the paper. The results presented that all the items were deemed equally important by respondents. The research also afford a actual instruction for course compilers and assisted the investigator polish up their their checklist which could be appropriate for assessing textbooks more securely.