Question

The light was on all day long.I didn't know who ____. A.has turned it on B.had turned it on

Answer 1

你好！
选B。根据was
可以判断整个句子的时态是过去时。等开了一整天，而根据答案开灯这个动作肯定是在灯亮之前，所以后一句应该是过去的过去发生的事情，所以是had
turned
it
on
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