问题补充：
, I lost heart in English learning, but my teacher said to me, “Keep on working hard, and you’ll succeed .”
A. At a time; in time
B. At one time; in time
C. At a time; on time
D. At one time; on time
答案：
A. At a time; in time
(答案→)B. At one time; in time
C. At a time; on time
D. At one time; on time
解析：句意：从前我对学英语失去信心了，但是我的老师对我说，“努力学习下去，迟早你会成功的”。at a time 依次,逐一,每次. at one time一度,从前. in general 一般的，大概 in advanced 预先 in time 及时，迟早的意思 on time 按时，所以答案是B。
考点: 考查介词短语的用法。
