问题补充：
, I lost heart in English learning, but my teacher often said to me, “Keep on working hard; you’ll succeed .”
A. At a time; in time
B. At a time; on time
C. At one time; in time
D. At one time; on time
答案：
A. At a time; in time
B. At a time; on time
(答案→)C. At one time; in time
D. At one time; on time
解析：考查词组：at a time一次，at one time曾经，一度，in time及时，迟早，on time准时，句意：我曾经对英语学习灰心，但老师经常和我说：一直努力，你迟早会成功的。选C。
