题目内容
The element radium, ______ in the chemistry lab, gave off a blue light.
A. discovering B. to be discovered C. to discover D. discovered
【答案】
D
【解析】略
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题目内容
The element radium, ______ in the chemistry lab, gave off a blue light.
A. discovering B. to be discovered C. to discover D. discovered
D
【解析】略