依靠政府，发动群众共同管理维护好输气管线，是（）的管理方法。
A.减轻维护工的工作量
B.克服人员不足
C.行之有效
D.管理工作现代化
参考答案：C
—I called you yesterday evening, but there was no answer.
—Oh, I'm sorry. I _______ dinner at my friend's home. [ ]
A. had
B. was having
C. have had
我国古代集大成的戏剧理论家是（）
A.李渔
B.李玉
C.沈璟
D.朱有墩
