Answer: Tan builds a central idea of her story analyzing the type of questions and how they can affect students' ability to write well.
Explanation:
Tan analyses the type of questions and exercises present in the test, and quoting her mother, she affirms that are too easy.
In the given example: "Even though Tom was foolish, Mary thought he was ridiculous." The adjectives foolish and ridiculous can be replaced by any other. In that way, Tan asserts that this kind of tests might affect students' ability to write well because they aren't putting real effort on solving them.