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(单选题)Your forced laughing is more noticeable than you think, main (单选题)What do researchers at the University of California want to (单选题)In which column can this passage be read? (单选题)The underlined phrase “phase out” in the last paragraph is c (单选题)According to the passage, carbon emissions may be reduced by (单选题)It can be inferred from the passage that ______. (单选题)What did the author realize in the end? (单选题)The author let his son repair the car because he believed th (单选题)What can we learn about the author’s children? (单选题)What used to be the author’s hope for his son?