问题补充:
Most students in my class are never in the morning classes.
A. of their best
B. for their best
C. in their best
D. at their best
答案:
A. of their best
B. for their best
C. in their best
(答案→)D. at their best
解析:固定词组。at their best处于最佳状态。句意:大部分的学生在上午的课上处于最佳状态。