【题目】We offer an excellent education to our students. ________, we expect students to work hard.
A.On average
B.At best
C.in return
D.After all

【答案】C
【解析】句意：我们为我们的学生提供优质的教育，相应地，我们期望学生努力学习。on average按平均数计算；平均；at best顶多；in return作为回报；after all毕竟。根据句意可知选C .