题目内容：
Hardly ______ when the door suddenly closed.
A. they had arrived
B. they arrived
C. did they arrive
D. had they arrived
参考答案：
选择题：Hardly ______ when the door suddenly closed.
- 题目分类：习题答案
- 题目类型：选择题
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Student A: I wonder whether you are satisfied with the new equipment. Student B:
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