问题补充：
Millie is getting on well with her friends but she is a little selfish .
A. in time
B. on time
C. at times
D. at a time
答案：
A. in time
B. on time
(答案→)C. at times
D. at a time
解析：句意：Millie正和他的朋友们相处得很好，但是她有时还是有点自私。A. in time 及时 B. on time 按时 C. at times有时相当于sometimes D. at a time作“一次，每次”讲，常用于“数词+at a time”的结构中.根据题意故选C
