Directly from my teaching experience and observation in the classroom teaching, I find students in class lack of enthusiasm in performing tasks, such as dialogues and group discussions. Many researchers believe the fact that Chinese are reluctance to communicate may be related to the traditional culture of our country. It is inherited from Confucian tradition. (Ellis, 2009) Ellis (2009: 224) also points out that the task may contain two aspects. One is “input – providing”, including listening and reading and the other is “output – prompting”, involving speaking and writing. However, due to China's national conditions, teaching mode still sticks to traditional teaching method. It over emphasizes the knowledge of grammar and vocabulary and ignores the applied language expression in the dialogues. A typical example is the College Entrance Examination, which pays little attention to speaking.

So teachers should distribute the limited time in class to the students, letting them practice their spoken English as much as possible. Avoid the dumb English, which is very terrible for English learners.

2. Literature Review 

2.1 Definition of TBI

Nunan regarded tasks as basic items in the language acquisition, just as the blocks in the building. The classroom activities involve learners' understanding, operation, product and interaction with the target language (Nunan, 1989:5). Breen (1987) defined tasks as a series of activities, which range from easy activities to the more difficult ones. Learners can improve their language competence during the process of completing them.

Specifically, a task is an activity that requires learners to engage in meaningful negotiations and natural communications. Real-life language may be used in the process of completing a variety of tasks, such as giving directions, making dialogues, writing letters etc. (Richards and Rodgers, 2005). Tasks are considered as the basic step of analyzing after setting goals, education activities and evaluations. (Van den Branden, 2006: 12)

With the regard to TBI, it is an approach based on the use of tasks as the central part of the language teaching. The methodology centers on a series of tasks students perform. Skehan believed that TBI works as an instruction where learners are given a series of tasks to finish in class. It can be assumed that performing tasks will take natural acquisition mechanisms, extend the potential internal language system and promote the development forward. (Skehan, 1998:95)

2.2 Previous Studies on Task-based Instruction 

The primary theory of TBI can be traced back to the Language Acquisition Theory of Krashen. The theory is composed of five parts. The kernel of Krashen's theory is the comprehensible input hypothesis that gives an explanation for the way people acquire language. Krashen firmly believed that comprehensible input is very necessary and significant for successful language acquisition. We acquire language by understanding input materials which are a bit higher than our current level of abilities.

Namely, “I” refers to learners’ current level of abilities and “I+1” means the level which is a bit higher than the current one.

Social Constructivism Theory thinks that learning and development are both activities which need social and cooperative work. It is significant and necessary for learners to emphasize contextualized learning and make sense of their environment. They may assimilate former comprehension with new concepts and thoughts in the new contexts. At this point，it can be said that the affective factor has long been lacking in the traditional Chinese EFL classroom．

3. Basic Steps and Design Principles 

3.1 Basic Steps of Task-based Instruction 

Willis (1996) provides the framework of TBI, as the following illustrates:

1) Pre-task: Teacher leads in a topic by the means of free-talk, brain-storming ideas, showing pictures, telling stories, singing chants, lip-contact, funny games, relating personal experiences etc. Then he/she interprets useful words and phrases in details and gives some exercises. At last, teacher makes sure that all the students understand the meaning of the subject and master the application to the new words and key sentences.  任务型教学法在初中英语语法教学中应用(2):http://www.youerw.com/yingyu/lunwen_60004.html