1，9，5，1，，（ ）。

(单选题)According to the third paragraph, this “fundamental confusio (单选题)As it is indicated in the second paragraph, the author finds (单选题)What do teachers think about teaching to the mandated state (单选题)What can be inferred about Erica at school? ( ) (单选题)The word “boomed” in the passage is closest in the meaning t (单选题)Why does the author mention practical inventions in paragrap (单选题)Which of the following can be inferred about Pennsylvania's (单选题)Which of the following best expresses the essential informat (单选题)According to paragraph 1. the U.S economy became the largest (单选题)关于敏捷软件开发中需要关注的风险，以下说法不正确的是（ ）。