结构基因（structural gene）

Structural unemployment 结构性失业

结构域(structural domain)

结构酶(structural enzyme)

The structural syllabus does not have a strong linguistic basis. The aim of the structural syllabus is specifying the situations in which the target language is used.（）

What are the structural and post-structural views toward errors

With the development of applied linguistics, there have grown two kinds of attitudes toward learners’ errors. The structuralist view of errors was dominant in the field of applied linguistics until the end of AIF0. The structuralist linguists follow the behavioristic view that to learn is to change old habits and build new habits. In their opinion errors occur when the learner fails to respond correctly to a particular stimulus in the second language because the features of the second language differ from those of the native language and the learner tends to carry over features of the native language into the second language. In other words, the learner fails to change his old habits so as to acquire new habits of the second language. Since an error may serve as a negative stimulus which reinforces "bad habits", so it should not be allowed to occur.
With the development of TG grammar and other linguistic theories, some changes of attitudes to errors have taken place. First of all, the nature of language is viewed differently—learning a language involves making constant hypotheses about the structure of the target language. The learner tests his own hypothesis against what the native speaker says. The errors he makes are actually his incorrect hypothesis about the new language. The post-structuralists regard errors as evidence of the learning process. By making hypothesis about the target language, the learner arrives at a particular interlanguage. Then he modifies his hypothesis and goes towards the target language. Obviously, errors can be found at the stage of interlanguage. They hold that errors are significant in three aspects:
(a)They tell the teacher, if he undertakes a systematic analysis, how far towards the goal the learner has progressed and consequently what remains for him to learn.
(b)They provide the researcher with evidence of how language is learned or acquired, what strategies or procedures the learner is employing is his discovery of the language.
(c)They are indispensable to the learner himself, because we can regard the making of errors as a device the learner uses in order to learn. It is a way the learner has of testing his hypothesis about the nature of the language he is learning. The making of errors then is a strategy employed both by children acquiring their mother tongue and adults learning a second language.

please compare the structural features of jejunum and ileum(5分)