【名词&注释】
高尚情操(lofty sentiment)、爱岗敬业(cherishing the job devotionally)、出现问题、等差数列(arithmetic progression)、以身作则(set an example)、严于律己、遇到困难(encounter difficulties)、廉洁奉公(clean and devoted)、《中小学教师职业道德规范》、心平气和(ataraxy)
[单选题]2/5,-3/7,4/9,-5/11,( ).
A. 6/11
B. 6/13
C. 7/13
D. 一7/13