The Research on PDA Class in Comprehensive English Teaching from Eco-view

: With the reform of College English teaching, many scholars from the perspective of ecology, combing with the elaboration of the concept of ecological education and the current situation of College English teaching came up with The College English classroom teaching. Other scholars have analyzed the application of sub-classes in integrated English teaching in order to enhance students' learning initiative and improve classroom teaching effect. Based on the previous studies of scholars, this paper introduces the perspective of ecology and the connotation of Pad class pedagogy in detail, and then combines the existing problems in College English classroom teaching with systematic and comprehensive eco-classroom language method, puts forward the application of sub-classes in English and Chinese teaching from the perspective of ecology. This study provides a new way for the reform of sub-classes in College English teaching from the perspective of ecology.


Introduction
At present, many English classes still focus on the single teaching of teachers in College English teaching in the 21st century. There is a lack of meaningful interaction or real exchange of ideas between teachers and students, ignoring that comprehensive English is a course that includes listening, speaking, reading, writing and translation, which makes the students trained in Colleges and universities incompatible with the goal of personnel training in China. Finally, the imbalance between teaching and learning in the educational ecosystem appears, resulting in the imbalance between teaching and learning. In view of the unbalanced teaching system, Professor Zhang Xuexin of Fudan University, through many years of teaching practice and theoretical thinking, has innovatively put forward the teaching mode of "PAD(presentation-assimilation-discussion)" on the basis of the advantages of unified classroom teaching, and it has been widely used and praised in Chinese universities. Therefore, this paper combines the educational concept of ecology with the teaching model of PDA class, explores the teaching strategies and methods in English classes, aiming at establishing an ecologically-based English classroom with teacher-student interaction, harmonious environment and independent development, and constructing a sustainable foreign language ecology class.

An Overview of Ecological View
First of all, we need to introduce the development and meaning of ecological concept. Ecology was founded in the 1960s by Haeckel, a German biologist.
The first related concept of biology was put forward. Its research goal is to study the relationship between biology and environment. In the course of its development, many scholars in various fields extended and internalized the principles of ecology and studied human and nature, human and social environment.
The core of relationships is putting people at the core: in the 1970s, another scholar, Lawrence Cremie, first mentioned it.
The concept of "educational ecology" was put forward. Based on the basic principles of ecology and the viewpoint of ecological balance, he studied the dynamic map of educational phenomena through the method of system theory. Since then, many scholars and educators have begun to combine the concept of educational ecology with all aspects of education and teaching. In the 1980s, educators introduced ecology into classroom teaching in large numbers, and formed an ecological classroom teaching concept.
There are three ecological elements in the teaching theory of English ecology. The first is the law of limiting factors. As far as college English teaching is concerned, teachers' present teaching ideas and students' learning attitude, lacking of learning subjectivity and the community environment constitute the main limiting factors in English classroom teaching. Secondly, the law of affiliation and the most appropriate principle include the thinking intensity between students, the difficulty and progress of teachers' teaching, the most appropriate teaching resources and teaching design of schools, and finally, the principle of educational niche. As far as English teaching is concerned, in English classroom teaching, teachers should treat students with different niches equally according to this principle, and integrate some excellent and different teaching methods according to students' personality characteristics.
There are two main parts of ecological view in College English primary school. First, the ecological subject of teaching, that is, teachers and students, is well known. Every teacher has his own unique comparative learning idea and teaching style, and every student's learning behavior has its own distinct personality characteristics. Teachers and students constitute the social situation of individuals and others in the English learning classroom play a different roles, secondly, students' environment, before the introduction of the concept of ecology teaching, in the previous classroom teaching, the interaction between teachers and students is poor, teachers may not act towards their children, that is, two eyes closed one eye, but after the introduction of ecology teaching, ecology refers to the traditional classroom teaching words, classroom English teaching atmosphere and physical teaching environment, of course, including the psychology of teachers and students. The ecological view of English teaching embodies the relationship between classroom teaching and ecological environment. This doctrine can be used to rebound and communicate in the environment of student-centered teaching, and to broaden the knowledge horizon and richness of English majors.

The Meaning of PAD Class
PAD class is a teaching mode which integrates the traditional teaching mode with the theory-based teaching mode.
It can give full play to the advantages of the two teaching methods and make up for the weaknesses. It is helpful to cultivate students' practical application ability of English. The core idea of the sub-class is to allocate part of the classroom time to teachers and the other part to students for interactive learning in the form of discussion. The time allocation of the two teaching methods can be determined according to the specific situation. Teachers' teaching behavior is divided into teaching, internalization, absorption and discussion. These three teaching activities are interlinked and progressive, each with different teaching objectives and tasks. The three teaching behaviors are separated from each other, but there are interrelated parts in content. In the specific teaching process, it can be divided into three stages: pre-class preparation, classroom listening and discussion, after-class discussion and summary. In the PAD class teaching, students can first find relevant information, supplement learning related knowledge, prepare for listening and discussion by mistake, and emphasize the principle of teaching before discussion in the classroom listening and discussion link. Teachers teach knowledge points and contents at first, then students complete the internalization of knowledge according to their own understanding and specific problems, and after that, student need to discuss on learning and absorption. Teachers encourage students to arrange their study independently after class. For questionable problems, they can discuss with each other between teachers and students, so as to carry out personalized internalization and absorption. In addition, English teachers report on teaching problems to the group leaders, interact with students in the classroom, and make comments and summaries on students' views. The innovation of each other's class lies in the staggering of lecture time and discussion time. In the separate classroom teaching, the combination of these three teaching behaviors and teaching process is beneficial to the improvement of students' independent learning and thinking ability. It helps to cultivate students' autonomous learning ability In addition, for the evaluation of the teaching effect of PAD class, combine process evaluation with summative evaluation. According to the content and link of English teaching, the emphasis of process evaluation and summative evaluation is different. For example, in teaching new knowledge and grammar, summative evaluation is emphasized, but in communication, the process evaluation is emphasized, which integrates students' classroom discussion, learning achievement report and homework completion. To enable students to actively participate in the classroom according to their learning objectives, needs and interests, which not only fully mobilizes students' desire to learn English independently, but also fully cultivates students' ability to think independently and study independently.

Dated Teaching Pattern
At present, in many colleges , the target of English competence training by students is not clear, which leads teachers to adopt the traditional teaching mode in English teaching, that is, the teaching mode of "Cramming education". Students lose their motivation to learn English and lose interest in English lessons. From the point of view of ecology, students can only improve their ability of memorizing and can not acquire the practical application ability of English in this teaching mode. Teachers or schools ignore the influence of other environments, especially society, campus and culture on the interaction between human and environment. The traditional examination-oriented English teaching method emphasizes the management and monitoring of the classroom environment and order, which leads to the disharmony and imbalance of the two in the classroom ecosystem. Instead of combining listening, speaking, reading, writing and translation in class, it is a single, fragmented teaching. In the 21st century, with the development of information technology and equipment in colleges and universities, multimedia equipment and technology has been popularized in colleges and universities. Although most teachers use modern information technology to assist in classroom teaching, many teachers just replace the traditional "blackboard" with the modern "screen", which only saves the complexity of their own writing.

The Students' Ability of Comprehensive Application of English, such as Listening, Speaking, Reading, Writing and Translation, is Insufficient
In comprehensive English teaching, students and teachers' understanding of learning English only exists at the level of passing the exam. Therefore, in order to improve the pass rate of CET-4 and CET-6, many students or teachers only pay attention to English reading, translation and other parts, because of its large proportion of scores, resulting in students' contempt for the listening and speaking parts of English. This mode of teaching makes students unwilling or unconsciously to participate in the comprehensive English classroom listening, speaking, writing activities, only focus on words and questions, but also make the classroom interactive atmosphere dull, students' participation enthusiasm is not high. In order to achieve the goal of teaching scores and achievements, teachers help students pass the exam and turn the classroom into a mechanical training class, while neglecting the cultivation of students' comprehensive language ability. It also leads to a low level of oral English. Students, because of their lack of oral ability, interact with their teachers in Chinese to express their views on the topic in classroom teaching activities, and the teachers do not have a very good solution, so they ignore or look at each other without words. An interactive activity that makes it difficult to engage in topic discussions. Trained students can only read English, but can not communicate with foreigners in English.

Teaching Strategies of PAD in Comprehensive English Teaching from the Perspective of Ecology
By expounding the concept of ecological English teaching and the teaching mode of PAD class， it can be found that this concept and teaching mode are based on fully respecting the individual differences of students' learning, and on the basis of comprehensive English teaching. It is helpful to improve students' ability of comprehensive application of English, such as listening, speaking, reading, writing and translation, so as to help students express their ideas actively through various forms of English. Therefore, by synthesizing the teaching idea of the ecological view and the advantages of the PAD class teaching mode, this paper puts forward the teaching strategies of PAD class in the comprehensive English teaching from the ecological perspective.

Building PAD Class of Teacher-Student Interaction
College English classroom from the perspective of ecological view embodies the concept of "student-oriented" teaching. In the comprehensive English teaching, teachers need to make clear the position of teachers and students in the classroom, and give the initiative of English learning to students. As long as the teacher's duty is to guide and organize the development of activities. Design more teaching tasks and activities for students' English learning. For example, the teaching activities of listening, speaking, reading, writing and translation can be rich and colorful, and the form of dialogue between teachers and students can be carried out, and students can communicate and communicate in an interactive and cooperative manner on a certain topic, and at the same time, they can express their views by speaking, writing and writing. In order to mobilize the enthusiasm of students to participate in it. At the same time, the communication and interaction of comprehensive English topics, and the ecological perspective of equal communication, mutual benefit and win-win. Interaction not only helps students internalize and absorb classroom knowledge, but also improves students' understanding of English knowledge. This can not only build a harmonious relationship between teachers and students, but also facilitate the effective development of various classroom teaching activities. From the perspective of ecological view, the interaction and cooperation between teachers and students is more embodied in mutual cooperation and exchange in terms of building a harmonious and common learning relationship between teachers and students. In the interactive PAD class, it is beneficial to better reflect the harmonious progress of teacher-student relationship.

Improve Students' Comprehensive English Ability
In the process of PAD class mode, teachers can make use of modern information technology to carry out real English comprehensive teaching of listening, speaking, reading, writing and translation. For example, in the aspect of listening and speaking, a new teaching software is introduced, and the spoken language dialogue between foreign teachers and foreign teachers is carried out on the Internet, so that the teaching environment and actual operation are realistic. And teachers and students through oral dialogue. It is also possible to set up a simulated English dating and business dialogue situation, which can effectively combine the internal learning knowledge with the practical application, and help the students to have a better understanding of the benefits of learning knowledge. It can give students the opportunity to test themselves in practice.

Establishment of Evaluation Mechanism for PAD Topic Teaching
From the perspective of ecological view, it is helpful for teachers and students to define their "ecological niche" by establishing the teaching evaluation of PAD-topics. Under the background of cultivating students' comprehensive English application ability, colleges and universities should gradually construct a model of combining process evaluation and result evaluation. On the one hand, the school evaluates teachers' performances and results in PAD class in five aspects: listening, speaking, reading, writing and translation. On the other hand, teachers should give quantitative feedback on students' learning content and classroom performance, English communicative competence and test results in order to find out the essence of the problem and help students realize their own shortcomings. Also reflect on their own teaching problems. So as to improve students' English comprehensive ability.

Conclusion
The research in this paper combines the knowledge of ecology and pedagogy and studies the classroom teaching of college comprehensive English from an interdisciplinary perspective, which not only provides a new perspective for classroom English teaching in colleges and universities, but also provides a new perspective for classroom English teaching in colleges and universities. At the same time, it also provides theoretical basis for solving the problems in college English teaching. It is also hoped that through the research and analysis of this paper, we can promote the further improvement and innovation of the teaching concept and teaching mode in colleges and universities to a certain extent, and at the same time improve the students' interest and enthusiasm in English learning. To increase the interest of comprehensive English teaching courses, thus cultivate the composite talents welcome of social and enterprise.