Krashen (1985: 157) points out that the best way to teach students is to provide comprehensible input which is suitable for the learner’s language level. When children learn their mother tongue, they are not taught grammar rules, but the rules can be acquired when the learners have enough input. Language acquisition will be realized when the teacher provides effective comprehensible input. Therefore, language acquisition is closely linked to language input. On the basis of the comprehensible input theory, the i+1 formula, proposed by Krashen (1985: 216), this paper intends to analyze the effective approaches and the application in the three stages of the teaching of English reading with the hope to improve students’ learning effect.

2. Literature Review源.自|优尔,:论`文'网www.youerw.com

2.1 Researches of Input Hypothesis 

2.1.1 The Input Hypothesis

     For many years, Stephen Krashen has been doing researches on language learning, the acquisition of second language foreign language and the methodology of foreign language teaching. In order to facilitate language acquisition, he studies the rules of foreign language teaching. The most eminent theory of the second language learning process is Monitor Model which consists of a set of five basic hypotheses: acquisition-learning hypothesis, natural order hypothesis, monitor hypothesis, flitter hypotheses and input hypothesis. 

As claimed by Krashen himself, the Input Hypothesis is the most important of the five, both theoretically and practically. The Input Hypothesis states that humans obtain language in only one way--by receiving comprehensible input. Language acquisition depends the understanding of what other people say. The input should be neither too difficult nor too easy for learners to understand. It is defined by Krashen in terms of the learners’ present level, named “i+1”. “I” represents learners’ current level while “1” represents the next level. It attempts to answer the critical question of how we acquire language. Therefore, the Input Hypothesis is only concerned with acquisition, not learning. Considering not all of the learners being at the same level of linguistic competence at the same time, Krashen suggests that natural communicative input is the key to designing a syllabus, ensuring that each learner will receive i+1 input that is appropriate for his current stage of linguistic competence. The Input Hypothesis has two corollaries: (1) Speaking is a result of acquisition and not its cause. (2) Speech cannot be taught directly but emerges on its own as a result of building competence via comprehensible input. (qtd in Shu Baimei 2012: 35-36)