17. (填空题) A mistake has nothing to do with the language competence, but a result from ___breakdown. When a mistake is challenged or given enough attention, it can be self-corrected. 2) An error, on the other hand, has ___relation with the learners’ language competence. Errors result from ___of knowledge in the target language. Language errors cannot be self-corrected no matter how much attention is given.(本题4.5分)