The central heating system of this office building is down and several workers ______ it right now. ...
2022-12-03 14:55:13 139次 2013-2014学年山东省德州市高三1月月考英语试卷（解析版） 单项填空 反馈错误 加入收藏 正确率 : 100%
题目内容：
The central heating system of this office building is
down and several workers ______ it right now.
A. had repaired B. have
repaired C. repaired D. are repairing
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