同一堂课中，有的学生专心听讲，有的学生心不在焉，长此以往，学生之间的学习成绩有了很大差异。这主要体现了（ ）对人的发展的作用。

(单选题)What is the writer trying to do in this passage? (单选题)The meaning of the underlined word “mature” in the passage i (单选题)Dennis’s example shows that successful people should _______ (单选题)From the story we know that the butterfly can’t fly because (单选题)Which sentence should go in the empty box in the last paragr (单选题)The first “it” in Paragraph 3 refers to（指的是）______. (单选题)What does the article mainly talk about？ (单选题)Sweet potatoes are good to people because they are rich in _ (单选题)From the passage we know that ______. (单选题)What can we know about sweet potatoes from the passage?