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How should he have known it? (What's the tense in this sentence? Is it like "How did he know it?")

How should he know it? (What's the tense in this sentence? Is it like "How does he know it?")

Please help me solve my doubt. Thank you!
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Closer to past perfect (it's typically before some event), than simple past to me.
Mostly present/future time.
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The modal verbs (like should, would, etc.) don't really have tenses in the same way that other verbs do.
You are right, however, that should is like the present, and should have is like the past. Your paraphrases are not really accurate, though.
How should he know it? ~ How can we expect him to know it (now)? (He has no way of knowing it.)
How should he have known it? ~ How can we expect him to have known it (then)? (He had no way of knowing it.)
CJ
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Thank you! I totally understand now!
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