问题补充：
—Have you finished your homework ?
--Not . I was playing computer games.
A. yet ,already
B. already ,yet
C. yet, yet
D. yet, yet
答案：
A. yet ,already
B. already ,yet
(答案→)C. yet, yet
D. yet, yet
解析：句意：--你已经完成你的作业了吗？--还没有。我正在玩电脑游戏。分析现在完成的疑问句形式要将already 改为yet, 否定句中也要将already 改为yet,故选C
