补写出下列名句名篇中的空缺部分。
______，可以攻玉。(《诗经·鹤鸣》)
参考答案：他山之石
—What was wrong with you yesterday evening?
—I ________ my homework when the light went off suddenly. [ ]
A. doing
B. was doing
C. did
D. have done
湿中少阴之阳
