Why is difficult to change real capital​

How does tan build a central idea of her story in the excerpt? tan discusses the types of questions on achievement tests to support the idea that the tests limit students' ability to write well tan explains a question on a language achievement test to support the idea that the tests shd d include more interesting content tan gives an example of her experience with achievement tests to support the idea that they are not always accurate measures of language ability tan considers how her mother might answer a question on a test to support the idea that nonstandard english limits a person's ability to communicate

Read this sentence. although the idea was foreign to me, i still thought i would give it a try.

So know lets geta real question what does this actually mean