问题补充：
, I lost heart in English learning, but my teacher often said to me, “Keep on studying hard , and you’ll succeed.”
A. At one time; in time
B. At one time; on time
C. At a time; in time
D. At a time; on time
答案：
(答案→)A. At one time; in time
B. At one time; on time
C. At a time; in time
D. At a time; on time
解析：考查time的词组。at one time以前，曾经；in time及时，最后；on time准时；at a time一次，每次；句意：曾经我对英语学习失去了信心。但是我的老师经常对我说：继续努力，你最终会成功。
