距离下课还有10分钟，学生注意力涣散，老师说：“如果大家认真听课就免去额外作业。” 学生又开始认真听课了，老师采取的措施是（ ）。

(单选题)According to Barry Schwartz, the customer model ______. (单选题)Which of the following most illustrates customer mentality? (单选题)We can learn that student satisfaction with a professor is m (单选题)Look at the four squares [A, B, C, D] that indicate where th (单选题)According to Para.2, the atmosphere on Mars would ______. (单选题)The author discusses environments (Line2) in Para. 2 in orde (单选题)According to Para l, which of the following is true of space (单选题)What can be learned from Dr. Kaminski? (单选题)What is most likely to work on dogs’ communicative ability d (单选题)The underlined word “dropped” (Line5, Para7) means “______ ”