Something has been happening to the concept of "fiction",
either in critical discourse and elsewhere. For a long time, __1__
this concept operated under common understood restrictions. __2__
It was used to refer to a certain genre of literature; a certain __3__
aspect of literature in general——the element of plot, action,
or fable, including such constituents like character, setting, __4__
scene, and so on; and to any narrative or story contained __5__
a large element of invention. But recently, the concept of
"fiction" has undergone an extension. Though still used to __6__
refer to the action or plot of literary work, it has come to __7__
be appllied to something more: to the ideas, themes, and
beliefs that are being embodied in the action or plot. It is __8__
not only the events in literature that are regarded as fictive
but the "message" or "world view" conveyed in the presentation
of the events as well. And this is not the end of the matter.
Gone a step further, critics now sometimes suggest, by a kind __9__
of tautology, that literary meanings are fictions although all __10__
meanings are fictions, this critical view asserts that "life" and
"reality" are themselves fictions.

答案及解析:
1. either—both
both...and...为固定搭配。

2. common—commonly
过去分词understood作定语，需要副词修饰

3. 在第二个a certain前加to
与前面的to短语并列，都为refer to所加的短语

4. like—as 或 删掉such
such...as为固定搭配。如删掉such则为单独由like引出所举的说明性的例子

5. contained—containing
现在分词做定语，相当于定语从句。

6. extension—expansion
extension与expansion为形近词，前者强调纵向的扩大，增加或延长，后者着重多方位的，全面的发展和扩大。

7. work—works
此处指的是文学作品，常用works。

8. 删掉being
整篇文章都为一般现在时。

9. Gone—Going
现在分词作状语，表示动作由主语发出。

10. although—because
应该是原因状语从句，而不是让步状语从句。