问题补充：
This CD-ROM can help you learn and have fun .
A. at times
B. on time
C. at the same time
D. in time
答案：
A. at times
B. on time
(答案→)C. at the same time
D. in time
解析：词义辨析。at times有时，偶尔；on time按时，准时；at the same time同时；in time及时。句意：这种光碟能帮助你学习同时又很有趣。所以选C。
