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(单选题)What is the response of many educators to the use of externa (单选题)What is true about the two groups of researchers mentioned i (单选题)Overall, what is the author’s opinion? (单选题)Why haven’t airlines been doing so well recently? (单选题)Why is the director mentioned in the first paragraph? (单选题)What does the author mainly argue in this article? (单选题)Which of the factors mentioned in the article is described a (单选题)With which of the following statements is the author most li (单选题)According to the article, how important is the genetic facto (单选题)According to the passage, what mistake do many people make?