When English as a foreign language is taught to children at the primary and early secondary levels of education, it is generally taught with a general education aim in mind--that is, it is regarded as a "good thing" for them to learn a foreign language as a part of a broad education. There is usually, however, no immediate and specific requirement for such children to make use of the language in any communicative situation. The purpose of learning the language is essentially a "deferred"   purpose, deferred till the tertiary   level of education, normally at university, where, it is agreed, a knowledge of English would be helpful in their academic studies. Immediate aims of learning English are defined by the requirements of examinations. Inevitably what is taught to primary and secondary level children is not a communicative knowledge of English language use, but a knowledge of how the rules of English operate. The language system is taught by means of systematic audio-lingual   drill and exercise techniques based on habit formation theory of learning and a structural description of English. This may be an effective manner of teaching English usage, but it is less certain that an understanding of how these rules are related to language in use for communicative purpose is an automatic result of this instruction. What the thousands of children succeed in learning in this way is what is necessary in order to pass examinations. Whether such examinations accurately reflect the uses to which English will be put at the tertiary level is another matter altogether. Adults, on the other hand, unless they are learning a foreign language for "pleasure" at evening institutes, as a "cultural" and social experience, are generally highly conscious of the use to which they intend to put it. That use is frequently associated with an academic or professional requirement; without a knowledge of the foreign language, their development in their chosen sphere of work could be restricted or at least adversely affected. We know from the passage that   _  .
audio-lingual techniques are the best way to teach English for communication language usage is the focus of foreign language teaching at primary and secondary levels foreign languages are usually taught to children as the key of a broad education adults usually don't know why they learn foreign languages