—Listen! There someone at the door. —It must be your sister. A. is; knocking B. is; knock C. are; kn...
2022-12-28 14:25:37 23次 2015年初中毕业升学考试（山东青岛卷）英语（解析版） 单项填空 反馈错误 加入收藏 正确率 : 100%
题目内容：
—Listen! There someone at the door.
—It must be your sister.
A. is; knocking B. is; knock
C. are; knocking D. are; knock
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