【正确答案】The Affective Filter Hypothesis is considered as one of the key factors for second language acquisition. The concept of “Affective Filter” was first proposed by Dulay and Burt as early as in 1977 and defined as “an internal processing system which subconsciously prevents language learners from language intake according to the elements called “affections” by psychologists. ” In 1985, Krashen put forward the Affective Filter Hypothesis on that basis. This hypothesis argues that learners’ affective factors will filter the language input, and the filter effect will directly affect the amount of language input the learners can accept. Learners with stronger motivation and confidence can acquire a great deal of language input and convert the input into language competence. Conversely, when language learners are of little learning motivation, low confidence, or strong anxiety, the affective barriers will be reinforced and then the affective filter will get higher accordingly, decreasing the language input acquired by the learners.